JP5633727B2 - Plasma sterilizer - Google Patents

Description

  The present invention relates to a plasma sterilization apparatus that uses discharge plasma to sterilize or disinfect an object to be processed attached to an object to be sterilized, and particularly to an object to be processed of a toxic and hardly degradable polysaccharide using plasma. The present invention relates to a plasma sterilization apparatus that sterilizes or disinfects.

  At present, sterilization using EOG, formalin and glutaraldehyde is in practical use as a medical sterilization method. When sterilizing Gram-negative bacteria such as E. coli, the cell wall may not be completely degraded, and endotoxins constituting the cell wall may be released. Endotoxin, also called endotoxin, causes excessive immune activity against animals, and may cause shock symptoms (endotoxin shock). Therefore, establishment of a reliable and efficient sterilization method for toxins including endotoxin and abnormal prions is strongly demanded.

  The use of high-energy plasma for the sterilization is also under consideration. However, the sterilization method using plasma is in the investigation stage and has not yet been put into practical use.

  A conventional plasma sterilization apparatus has a pulse electric field generated by applying an electric pulse to an electrode pair, a nitrogen radical contained in a plasma generated in a nitrogen atmosphere due to a fine streamer discharge generated by the application, and a fine streamer. There is a technique in which toxin is nitrided and oxidized by causing short-wavelength ultraviolet rays emitted from a nitrogen atmosphere due to discharge to act on the toxin to dissipate the toxin from the surface of the object to be treated (see, for example, Patent Document 1).

  However, the conventional plasma sterilization apparatus as shown in Patent Document 1 has a problem that only a sterilization object that fits into the restriction can be inserted between the electrodes due to the restriction of the discharge gap (distance between electrodes). In addition, even if a conventional plasma sterilization apparatus can insert a sterilization object into the discharge region, the discharge path is blocked by the sterilization object, and the discharge is stopped and plasma generation cannot be maintained, so that sterilization can be performed. There is no problem.

  In addition, the present applicant has proposed a plasma sterilization apparatus that converts oxygen gas into plasma to generate oxygen radicals and performs sterilization treatment in Patent Document 2. However, in the plasma sterilization apparatus of Patent Document 2, since plasma is unevenly distributed in the vicinity of the electrode and oxygen radicals are locally generated in the container for sterilization, it takes a long time to sterilize the entire object to be processed. Cost. Moreover, it has been found that only oxygen radicals generated by such a plasma sterilization apparatus are insufficient to sterilize the polysaccharide treatment object.

JP 2008-178679 A Japanese Patent No. 4006491

  The present invention has been made in order to solve the above-mentioned problems, and is capable of continuing plasma generation regardless of the arrangement of an object to be sterilized, and advanced sterilization that inactivates the toxicity of an object to be treated attached to the object to be sterilized. The object is to provide a plasma sterilization apparatus that has the ability to not only kill microorganisms (such as bacteria), but also proteins, polysaccharides, and glycoproteins that constitute microorganisms.

  In order to solve the above-described problems, the plasma sterilization apparatus according to the present invention has the following technical features.

(1) A storage container for storing an object to be sterilized, an electrode installed inside or outside the storage container, a gas supply means for supplying a gas into the storage container, and a high frequency for supplying a high frequency current to the electrode A plasma sterilization apparatus for supplying a high-frequency current to the electrode to convert the gas in the storage container into a plasma and sterilizing the object to be sterilized, wherein the frequency of the high-frequency current is 3 MHz or more, The electrode has an electrode part composed of a pair of electric wires through which currents flow in opposite directions in a local space, and the assembly of the electrode part is arranged so as to surround the space occupied by the sterilization target, The direction of the line of magnetic force induced by the electrode part is the direction toward the space, and the magnetic field induced by each electrode part is superimposed on the space or in the vicinity of the space.

(2) The plasma sterilization apparatus according to (1) above, wherein the electrode is composed of one or more long electric wires.

(3) In the plasma sterilization apparatus according to (2), a meandering shape in which the long electric wire reciprocates in parallel or perpendicularly to the specific direction with respect to a specific direction passing through the space occupied by the sterilization target, Alternatively, any one of spiral shapes surrounding the specific direction is provided.

( 4 ) In the plasma sterilization apparatus according to any one of (1) to ( 3 ), the gas supplied into the storage container by the gas supply means includes at least one of oxygen, air, and water vapor. Features.

( 5 ) In the plasma sterilization apparatus according to any one of (1) to ( 4 ), the object to be sterilized is placed in the storage container, is formed of a conductive material, and is electrically It is characterized by comprising grounded mounting means.

As in the present invention, a storage container for storing an object to be sterilized, an electrode installed inside or outside the storage container, a gas supply means for supplying gas into the storage container, and a high-frequency current to the electrode A plasma sterilization apparatus for supplying a high-frequency current to the electrode, converting the gas in the storage container into a plasma, and sterilizing the object to be sterilized. The electrode part is composed of a pair of electric wires through which currents flow in opposite directions, and the assembly of the electrode parts is arranged so as to surround the space occupied by the sterilization target, and the direction of the magnetic lines of force induced by each electrode part is Since the magnetic field induced by each electrode part is superimposed in the space or in the vicinity of the space, a strong electric field is generated by the magnetic field induced by the high-frequency current supplied to the electrode. Thus, the gas in the storage container is efficiently converted into plasma, and further, a magnetic field directed to the space occupied by the sterilization target is used, and ions in the plasma and active oxygen generated by the plasma are generated on the sterilization target. Can be continuously supplied, inactivate the toxicity of the object to be treated attached to the object to be sterilized, kill microorganisms (bacteria etc.) as the object to be treated, and further comprise proteins, polysaccharides, Even glycoproteins can be degraded.
In particular, since the frequency of the high-frequency current is 3 MHz or more, oxygen atoms can be easily converted into plasma.

  The plasma sterilization apparatus according to the present invention includes a pair of electric wires in which currents flow in opposite directions in a local space while simplifying the electrical wiring because the electrode is composed of one or more long electric wires. It becomes possible to form many electrode parts.

  The plasma sterilization apparatus according to the present invention has a meandering shape in which a long electric wire reciprocates parallel or perpendicular to the specific direction with respect to a specific direction passing through a space occupied by an object to be sterilized, or a spiral shape surrounding the specific direction. Since either of them is provided, it is possible to easily form a large number of electrode parts composed of a pair of electric wires in which currents flow in opposite directions in a local space.

  In the plasma sterilization apparatus of the present invention, since the gas supplied into the storage container by the gas supply means contains at least one of oxygen, air, and water vapor, more active oxygen can be generated.

  In the plasma sterilization apparatus of the present invention, an object to be sterilized is placed in a storage container, is formed of a conductive material, and has a mounting means that is electrically grounded. Alternatively, it is possible to prevent the placing means from being charged by ions, and it is possible to maintain a high sterilization ability by preventing deceleration of electrons or ions due to the charging and maintaining the amount of active oxygen generated.

1 is a configuration diagram of a plasma sterilization apparatus according to a first embodiment of the present invention. Arrangement of electrodes of plasma sterilization apparatus according to first embodiment of the present invention Sectional drawing of the storage container of the plasma sterilization apparatus which concerns on the 1st Embodiment of this invention Experimental results of the plasma sterilization apparatus according to the first embodiment of the present invention The block diagram of the plasma sterilization apparatus which concerns on the 2nd Embodiment of this invention. Sectional drawing of the plasma sterilization apparatus which concerns on the 3rd Embodiment of this invention. Sectional drawing of the plasma sterilization apparatus which concerns on the 4th Embodiment of this invention. Schematic explaining the shape of the long electric wire in the present invention

The plasma sterilization apparatus of the present invention will be described in detail below. 1 to 8 are diagrams illustrating an embodiment of the present invention.
FIG. 1 is a configuration diagram illustrating a first embodiment of the present invention. A basic configuration of a plasma sterilization apparatus according to the present invention includes a storage container 1 for storing an object 100 to be sterilized, and an inner side of the storage container 1. Or it has the electrode 2 installed outside, the gas supply means 4 which supplies gas in this storage container, and the high frequency supply means 3 which supplies a high frequency current to this electrode, and supplies a high frequency current to this electrode In the plasma sterilization apparatus for converting the gas in the storage container into plasma and sterilizing the object to be sterilized, the electrode 2 has an electrode portion composed of a pair of electric wires in which currents flow in opposite directions in a local space. The assembly of the electrode parts is arranged so as to surround the space occupied by the sterilization object 100, and the direction of the magnetic lines of force induced by each electrode part is the direction toward the space, and in the vicinity of the space or the space Each electrode part Induced magnetic field is characterized by the presence is superimposed.

  In the description of the plasma sterilization apparatus of the present invention, the expression “sterilization” is used, but this is not limited to simply sterilizing an object to be processed such as microorganisms, but also proteins, polysaccharides, sugars constituting microorganisms. It is a concept that includes “disinfection” treatment that decomposes even proteins and inactivates the toxicity of the object to be treated.

  Further, in the description of the plasma sterilization apparatus of the present invention, it is defined that “the direction of the magnetic lines of force induced by each electrode part is the direction toward the space (occupied by the sterilization target)”, which is the effect of the present invention. Needless to say, the direction of the lines of magnetic force induced by some of the electrode parts may be allowed to deviate from the above direction within the range in which the object to be sterilized can be sterilized.

  In the present invention, the “surrounding” does not necessarily mean that the entire region is surrounded, and a gap may exist as long as the plasma can be substantially superimposed to achieve sterilization efficiently.

Below, it demonstrates centering on 1st Embodiment which concerns on the plasma sterilization apparatus of this invention.
(First embodiment)
A plasma sterilization apparatus according to a first embodiment will be described with reference to FIGS.
FIG. 1 is a configuration diagram of a plasma sterilization apparatus according to a first embodiment of the present invention, FIG. 2 is an arrangement diagram of electrodes of the plasma sterilization apparatus described in FIG. 1, and FIG. 3 is a plasma sterilization described in FIG. FIG. 4 is a cross-sectional view of the storage container of the apparatus, and FIG.

  In FIG. 1, the plasma sterilization apparatus according to the present embodiment uses a glass tube 1 as a storage container for storing an object 100 to be sterilized. The glass tube 1 is provided with an electrode 2 formed by arranging a linear body bent in a meandering manner. The plasma sterilization apparatus of the present invention is characterized by the shape of the electrode, and details will be described later.

  The electrode 2 is supplied with a high frequency current of commercial frequency or higher, particularly 3 MHz or higher, and a high frequency supply means 3 for generating a magnetic field directed to the sterilization object 100 by the high frequency current, and oxygen gas or the like in the hollow portion of the glass tube 1. Oxygen gas supply device 4 as a raw material gas supply means for supplying a gas to be converted into plasma, an oxygen gas valve 41, a decompression device 5 for decompressing the inside of the glass tube 1, and an amount of decompression of the decompression device 5 Plasma sterilization of the bulb 51 and the placement shelf 6 which is disposed inside the glass tube 1 and is formed of a conductive material on which the object 100 to be sterilized is placed and which is formed by grounding. The device is equipped.

  The glass tube 1 as a storage container is formed in a cylindrical shape as a hollow cylindrical body, and can have a diameter of 200 mm and a total length of 450 mm, for example. The shape of the storage container is not limited to a hollow cylindrical body, and a hollow rectangular body or a hollow spherical body can be used.

  Moreover, as a material which forms a storage container, metals, such as glass and stainless steel, or ceramics are mentioned. In the case of glass, the electrode can be disposed either inside or outside the storage container. However, in the case of a metal material, the electrode needs to be installed inside the storage container. When an electrode is placed inside a metal material storage container, when current is supplied to the electrode, a magnetic field line directed toward the center of the storage container and a magnetic field line directed in the opposite direction are generated. The magnetic lines of force that have been removed are preferably erased by the wall of the metal material storage container, so that problems such as leakage of the magnetic field to the outside do not occur.

  As shown in FIG. 2, the electrode 2 used in the plasma sterilization apparatus of the present invention has an electrode portion composed of a pair of electric wires in which currents flow in opposite directions in a local space, as shown in FIG. The assembly of the electrode parts is arranged so as to surround the space occupied by the sterilization object 100. As shown in FIG. 2A, the electrode 2 in the local space has a pair of electric wires (a pair of electric wires (2a-1, 2b-1), (2a-2, 2b- 2) and the like, and two electric wires in each electrode portion are in a state where current flows in opposite directions. The distance L between the pair of electric wires constituting the electrode part and the distance L ′ between the two electrode parts are preferably the same, but are not necessarily the same distance (L = L ′) depending on the shape of the arrangement of the electrode parts. There is no need. In FIG. 1, a linear body (electric wire) to be bent is reciprocated at equal intervals in parallel with the longitudinal direction of the hollow cylinder. As a result, two electric wire intervals L in each electrode portion and two adjacent electrode portions The intervals L ′ are equal to each other.

  An electrode which is an assembly of such electrode parts can be composed of one or more long electric wires. As shown in FIG. 8, the long electric wire 2 is parallel to the specific direction X with respect to the specific direction X passing through the sterilization target (see FIG. 8A, in FIG. 1, the hollow cylindrical body is accommodated). The longitudinal direction of the container 1 is a specific direction) or a meandering shape reciprocating vertically (see FIG. 8B), or a specific direction as shown in FIG. 5 described later (the longitudinal direction of the storage container 1 of a hollow cylindrical body) ). And in the local space B enclosed with the dotted-line frame of FIG. 8, the electrode site | part which consists of a pair of electric wire through which an electric current flows mutually reversely is formed.

  By using the long electric wires shown in FIGS. 1, 5 and 8, it is possible to simplify the electrical wiring for connecting a plurality of electrode parts, and the currents can be easily reversed in a local space. It is possible to form a large number of electrode parts composed of a pair of electric wires through which the current flows.

  And the electrode 2 which is an aggregate | assembly of such an electrode site | part is arrange | positioned so that the space which the sterilization target object 100 occupies may be surrounded, as shown in FIG. In addition, it is preferable to use stainless steel or copper for the material of the electrode 2.

  As shown in FIG. 2A, the distance L (or L ′) between the pair of wires in each electrode site is determined depending on the magnitude of the high-frequency current flowing through the wire and the distance from the electrode site to the sterilization object. Is done. When the high-frequency current flowing through the electric wire is large, the electric wire interval L (or L ′) can be relatively large, and as the distance from the electrode part to the sterilization object increases, the electric wire interval L (or L ′) ) Is preferably larger.

  Furthermore, regarding the distance between the adjacent electrode parts, the space (for example, the storage container) occupied by the object to be sterilized by the magnetic field formed in each electrode part and the magnetic field in the opposite direction formed between the adjacent electrode parts At the center position) is preferably separated by a distance that does not form a magnetic dipole. More preferably, the distance L ′ between the pair of electric wires in each electrode part shown in FIG. 2A and the distance L ′ between the adjacent electrode parts are set to be the same as the magnetic field formed by the high-frequency current. The average intensity becomes uniform, and it becomes possible to generate plasma and active oxygen having a more uniform spatial distribution.

  By setting the lower limit of the frequency of the high-frequency current flowing through the electrode 2 to 3 MHz or more, it becomes difficult for ions to follow the frequency change of the induced electromotive force formed by the electrode, so that only the electrons are efficiently accelerated and oxygen atoms However, since it is easily ionized into ions and electrons, low temperature plasma can be generated.

  Therefore, although depending on the length of the long electric wire, the frequency of the AC power supply in the high-frequency supply unit 3 can be set in the range of 1 MHz to 10 GHz, preferably in the range of 3 MHz to 2.45 GHz.

  When an electric current is passed through an electrode portion composed of a pair of electric wires, magnetic lines of force (thin arrows) as shown in FIG. 2B are formed on the electric wires (2a-1 to 2a-3, 2b-1, 2b-2). These are combined to form a stronger induced magnetic field (lines of magnetic force) M (thick line arrows). Naturally, a magnetic field M ′ having the same magnitude and opposite direction is formed between two adjacent magnetic fields M.

  As shown in FIG. 3, the electrode parts in the present invention are arranged so that the direction of the magnetic lines of force M induced by each electrode part is the direction toward the space occupied by the sterilization target 100. In addition, since the magnetic field induced by each electrode part is superimposed in the space occupied by the sterilization target or in the vicinity thereof, it becomes possible for plasma and active oxygen to reach the sterilization target sufficiently.

  In the plasma sterilization apparatus of the present invention, each electrode part is disposed so as to surround the space occupied by the object to be sterilized. Therefore, as shown in FIG. 3, from the entire surface of the storage container surrounding the object to be sterilized, A sterilization in which an active oxygen species generated by collision of electrons or ions accelerated by an electric field induced by this superimposing magnetic field with oxygen molecules is placed inside the storage container. It reaches the object and can be sterilized efficiently on the entire three-dimensional surface.

  Further, when the storage container is a square (see FIG. 7), the magnetic field in the central portion becomes the largest due to the interaction of the lines of magnetic force, although it is different from the situation of gathering at the center point of the circle. Moreover, when the storage container is spherical, the concentration effect of the induced magnetic field becomes very large.

  In the electric field induced by the induction magnetic field as shown in FIG. 3, the gas in the storage container 1 is turned into plasma. Plasmaization is performed in the vicinity of an electrode portion composed of a pair of electric wires in which a magnetic field changing at a high frequency exists, but the plasma moves along the magnetic field toward the center of the storage container, and the electrodes (2a, 2b) It becomes possible to generate plasma having a relatively uniform density distribution from a position closer to the center by several mm to several cm from the position toward the center.

  By such plasma distribution, sterilization is efficiently performed near the center of the storage container. Moreover, since almost no plasma is generated in the vicinity of the electrodes (electric wires 2a and 2b) and outside thereof, the electrodes are prevented from being damaged or deteriorated by the plasma.

  The gas introduced into the storage container 1 is not limited to oxygen gas as long as it generates active oxygen species by plasma. For example, air or water vapor can be used. This is advantageous in terms of cost because it is a gas that exists in the immediate vicinity. In addition, sterilization by reactive oxygen species generated from gas containing oxygen molecules, for example, oxygen gas, air and water vapor is different from other active oxygen species, for example, hydroxyl radical, because the sterilization residue is harmless. There is also an advantage that it is easy to handle. In addition, sterilization by reactive oxygen species, unlike other reactive oxygen species, for example, nitrogen radicals, does not physically and chemically decompose the sterilization target 100 itself, so that the sterilization target is damaged. It also has the advantage of exhibiting high sterilization ability without having to.

Hereinafter, a specific sterilization operation of the present embodiment based on the above configuration will be described.
In the present embodiment, as shown in FIG. 1, first, an object 100 to be sterilized is placed on a placing shelf 6 inside a glass tube 1 that is a storage container, and the glass tube 1 is sealed. Next, the inside of the glass tube 1 is decompressed using the decompression device 5 by operating the valve 51, the valve 41 is opened, and oxygen gas is supplied to the glass from the oxygen gas supply device 4 through the supply holes at an appropriate flow rate. Introduce into tube 1.

  Next, high frequency (including microwaves) in a band normally used in industry is applied to the electrode 2 to flow a high frequency current. As the frequency of the high frequency, 13.56 MHz can be used, and further, 2.45 GHz which is a frequency in the microwave band can be used. These are usually used with a power of about 50 W at a high frequency and about 500 W at a microwave. The electrode 2 generates plasma by a high-frequency current, and generates active oxygen species and oxygen ions by collision of electrons and oxygen molecules in the glass tube 1. This reactive oxygen species has a strong oxidizing action on proteins, carbohydrates and lipids constituting the fungus, and can be decomposed and killed by this oxidizing action. Note that oxygen ions also partially function when decomposing proteins, carbohydrates, and lipids attached to the surface of the object to be sterilized.

  Next, the active oxygen species generated by the secondary charge exchange collision between the accelerated ion and the oxygen molecule collide with the sterilization target object 100 placed inside the glass tube 1. Thus, since the active oxygen species are accelerated and collide with the object 100 to be sterilized from a plurality of directions, the active oxygen species have physical energy in addition to the chemical sterilization action by this acceleration. The sterilization ability for the sterilization target 100 can be improved, and the toxicity of the toxic and hardly degradable sterilization target 100 such as endotoxin, which is difficult only by reactive oxygen species, can be inactivated.

  Further, as shown in FIGS. 1 and 3, since the electrode 2 is reciprocated at equal intervals in parallel with the longitudinal direction of the hollow cylinder, a strong magnetic field M efficiently superimposed in the vicinity of the electrode 2 is obtained. And the velocity of ions is increased by the electric field induced by the magnetic field M, and the kinetic energy of the active oxygen species generated by the charge exchange collision is increased, so that the sterilizing ability of the active oxygen species can be improved. Further, since the sterilization target 100 is not placed between the two electrodes that generate the discharge, the weakening of the discharge by the sterilization target 100 can be prevented and the plasma generation capability can be maintained.

  Moreover, the size of the glass tube 1 that houses the sterilization target 100 can be, for example, 200 mm in diameter and 450 mm in length, and a sufficient space for placing the sterilization target 100 can be obtained. For this reason, sterilization can be performed efficiently without depending on the size of the object 100 to be sterilized. The glass tube 1 may be a glass tube having a diameter of 400 mm and a total length of 600 mm. In this case, a larger sterilization object 100 can be placed, and the present invention is used industrially. Above, it will be very useful. In addition, since the mounting shelf 6 is formed of a conductive material and grounded, ions generated by plasma can be prevented from being charged to the mounting means, and the ions are decelerated due to this charging. High sterilization ability can be maintained by preventing and maintaining the production amount of active oxygen. As described above, the present invention makes it possible to perform a large volume of plasma processing under low-pressure conditions, which has been difficult to implement in the past, and it is possible to put the plasma sterilization treatment into practical use by improving the amount of sterilization treatment. it can.

(Second Embodiment)
A plasma sterilization apparatus according to a second embodiment of the present invention will be described with reference to FIG. In FIG. 5, each number has the same meaning as in FIG. In this embodiment, a long U-shaped electric wire is wound around the cylinder as it is, and the U-shaped unsealed end is used as a power input terminal (one is a terminal for a high-frequency power source and the other is a ground terminal). Thus, it is also possible to configure the electrode 2 with a long electric wire and set it in a spiral shape surrounding a specific direction (longitudinal direction of the hollow cylindrical body) passing through the sterilization target.

  That is, in the plasma sterilization apparatus of the present invention, the case where the storage container is formed of a hollow cylindrical body will be described as an example. As shown in FIG. The electrode 2 may be formed so as to be parallel to the direction and over the entire inner circumference of the hollow cylindrical body, and as shown in FIG. 5, the electrode 2 is spirally wound on the circumference of the hollow cylindrical body. It is also possible to arrange by rotating and extending in the axial direction. Further, the bending method and the winding method may be used in combination. In this case, the power application is not necessarily performed simultaneously, and may be alternately applied periodically. In addition, when winding in a spiral shape, a desired electrode can be easily formed by simply winding a long U-shaped wire around a cylinder and using the U-shaped unsealed end as a power input terminal. be able to. Of course, an electrode can also be easily formed by winding two electric wires in parallel and setting the electric power input to each electric wire in the opposite direction.

(Other embodiments)
Further, a plurality of long electric wires 2 meandering parallel to the X direction as shown in FIG. 8A and a plurality of long electric wires 2 meandering perpendicular to the X direction as shown in FIG. It is also possible to arrange the electrodes so as to surround the sterilization target object 100 by arranging them at positions 6 and a2 in the depth direction (X direction) of the drawing.

  Furthermore, the elongate electric wire 2 of FIG. 8 (a) or (b) is arrange | positioned in the position of the code | symbol b1-b4 inside the storage container 1 which has a square cross section like FIG. It is also possible to arrange the electrodes so as to surround the object 100.

(Experimental example)
Experiments were performed under the following conditions, and the results shown in FIG. 4 were obtained. In the figure, a curve A shows an experimental result by the plasma sterilization apparatus of the present invention, and a curve B and a curve C show the experimental result by the conventional plasma sterilization apparatus as a comparative example. This curve B is the experimental result by the conventional hydrogen peroxide gas plasma sterilizer, and this curve C is the experimental result by the conventional ethylene oxide gas plasma sterilizer. In addition, beta glucan which is a substitute substance for endotoxin was used as the decomposition target, and the confirmation of the decomposition was performed with an infrared absorptiometer. Specifically, decomposition of beta glucan, which is a decomposition target, was confirmed based on a change (decrease) in the peak height of CH bonds at a wavelength of 2925 cm ⁻¹ in an infrared absorption spectrum. This utilizes the fact that the amount of CH bonds constituting the beta glucan decreases with the degradation of beta glucan, which is a polysaccharide.

(Experimental conditions)
1. 1. Plasma: Low-pressure capacitively coupled plasma 2. Discharge method: high frequency glow discharge Storage means internal pressure: 70 Pa
4). Plasma generation power source: High frequency power source (13.56 MHz)
5. Plasma generation power: 50W
6). 6. Source gas: mixed gas of oxygen (98%) and nitrogen (2%) Sterilization target: Yeast-derived beta glucan (5 mg / cm ² )

  From this experimental result, the plasma sterilization apparatus of the present invention has a decomposition rate exceeding 90%, whereas the conventional plasma sterilization apparatus has a decomposition rate of about 75% at most. It was confirmed that the resolution was twice or more. Curve B had a limit of up to 80 minutes due to the tolerance limit of the equipment (apparatus) by the sterilization treatment of the hydrogen peroxide gas plasma sterilizer. Similarly, curve C had a limit of processing time of up to 180 minutes due to the tolerance limit of the equipment (device) by the sterilization processing of the ethylene oxide gas plasma sterilizer.

From this experimental result, the plasma sterilization apparatus of the present invention was able to confirm a high resolution that the decomposition rate reached 90% when the processing time passed about 250 minutes. A plasma sterilization apparatus is generally an apparatus that performs sterilization by surface treatment, and the concentration of degradation target substances (endotoxin, beta glucan, etc.) in practical use is on the order of nanograms to micrograms per 1 cm ^2. From this result, it is considered that the degradation rate of 90% or higher for beta glucan having a concentration as high as 5 mg / cm ² in the present experimental result reaches almost 100% when the degradation rate is 90% or more. In this plasma sterilization apparatus, beta glucan, which is an alternative substance to endotoxin, is used as an object to be decomposed, but keratin, which is a similar substitute substance, can also be used as an object to be decomposed.

  As described above, according to the present invention, plasma generation can be continued regardless of the arrangement of an object to be sterilized, and it has a high sterilization ability to inactivate the toxicity of an object to be treated attached to the object to be sterilized. It is possible to provide a plasma sterilization apparatus that not only kills microorganisms (bacteria and the like) that are objects to be treated but also can decompose proteins, polysaccharides, and glycoproteins that constitute the microorganisms.

1 Storage container (glass tube)
2 Electrode 2a, 2b Electric wire 3 High frequency supply part 4 Oxygen gas supply device 41 Valve 5 Pressure reducing device 51 Valve 6 Placement shelf 100 Sterilization object

Claims (5)

A storage container for storing an object to be sterilized, an electrode installed inside or outside the storage container, a gas supply means for supplying a gas into the storage container, and a high-frequency supply means for supplying a high-frequency current to the electrode In a plasma sterilization apparatus for supplying a high-frequency current to the electrode to turn the gas in the storage container into a plasma and sterilizing the object to be sterilized,
The frequency of the high-frequency current is 3 MHz or more,
The electrode has an electrode part composed of a pair of electric wires through which currents flow in opposite directions in a local space, and the assembly of the electrode part is arranged so as to surround the space occupied by the sterilization target, A plasma sterilization apparatus characterized in that the direction of the magnetic field lines induced by the electrode parts is a direction toward the space, and the magnetic fields induced by the electrode parts are superimposed in the space or in the vicinity of the space.   2. The plasma sterilization apparatus according to claim 1, wherein the electrode is composed of one or more long electric wires.   3. The plasma sterilization apparatus according to claim 2, wherein the elongated electric wire reciprocates parallel or perpendicular to the specific direction with respect to a specific direction passing through a space occupied by the object to be sterilized, or the specific direction. A plasma sterilization device comprising any one of the spiral shapes surrounding the. The plasma sterilizing device according to any one of claims 1 to 3, the gas supplied to the storage container by the gas supply means, an oxygen plasma sterilization apparatus, characterized in that it comprises at least one of air or steam . The plasma sterilizing device according to any one of claims 1 to 4, in the storage container, placing the The sterile objects, while being formed of a conductive material, electrically grounded placing means A plasma sterilization apparatus comprising:

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