JPH0237183B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a microwave discharge plasma sterilizer used for sterilizing medical instruments and the like.

BACKGROUND ART Conventionally, heat sterilization using high-pressure steam or high-temperature air, gas sterilization using ethylene oxide gas, ultraviolet sterilization, radiation sterilization, etc. have been widely used to sterilize medical instruments and the like.

In heat sterilization, the object to be sterilized is exposed to high-pressure steam or high-temperature air, which typically reaches temperatures of 100°C or higher, so the materials that can be sterilized must be heat resistant and are extremely limited. Therefore, this drawback cannot be avoided no matter what heating means is used.

Gas sterilization is a method in which a sterilizer is made into a gas and filled into a container, and the gas concentration, temperature, humidity, pressure, etc. are adjusted so that it acts on bacteria.
Can be sterilized at low temperatures. For example, ethylene oxide is used for this gas sterilization, but the above-mentioned conditions are not easy to adjust, and the effects are significantly affected by variations in conditions. In addition, gas sterilization takes a long time to sterilize, and if the object to be sterilized has a complicated shape, the gas may not penetrate sufficiently and sterilization may not be carried out properly. The gas adsorbs to the object to be sterilized,
Since it remains for a long time, it has the disadvantage that the object to be treated cannot be used immediately after sterilization.

Furthermore, although ultraviolet sterilization exerts its sterilizing effect in an extremely short period of time, the sterilizing effect decreases as the intensity of the ultraviolet rays decreases due to dirt on the ultraviolet lamp, and if the density of bacteria is 10 ⁴ /cm ² or higher, the bacteria themselves become dark. Due to its effectiveness, areas that are shaded cannot be sterilized.

Furthermore, radiation sterilization requires large-scale equipment and is generally unsuitable for normal use.

A sterilization method using electric discharge or plasma is known as a method for solving the above-mentioned drawbacks of the sterilization method. A conventional example of a discharge sterilizer is, for example,
-35715, JP-A-57-195461, and JP-A-57-200156. However, in all of these known discharge sterilizers, a discharge electrode is placed in a vacuum container, and in order to apply a high voltage to this discharge electrode to cause discharge, the electrode is spattered with ions generated by the discharge. The spattered material adheres to the object to be sterilized, causing contamination in a sense other than sterilization.

Problems to be Solved by the Invention The present invention solves the problem of limiting the number of objects to be sterilized due to high temperatures in conventional heat sterilization methods, the problem of residual toxic gas in gas sterilization methods, and A microwave discharge plasma sterilizer that solves the problem of uneven sterilization and the contamination of objects to be sterilized by spatter from electrodes in the discharge sterilization method, and can perform clean and sufficient sterilization at low temperatures in a short time. Our goal is to provide the following.

Means for Solving the Problems In order to achieve the above object, a microwave discharge plasma sterilizer according to the present invention has a method for storing objects to be sterilized in a vacuum container equipped with an exhaust port connected to an exhaust system and a gas introduction port. In addition, a microwave introduction device is installed in the vacuum container to introduce microwaves into the vacuum container to generate plasma inside the vacuum container, and a magnetic field that generates a magnetic field to control the plasma state inside the vacuum container. It is characterized in that a device is provided, which magnetic device can consist of a permanent magnet or a magnetic coil.

Function With the above-described configuration, in the microwave discharge plasma sterilizer of the present invention, objects to be sterilized are placed on the processing shelf and evacuated to a predetermined pressure.
And inside the vacuum container, there is a gas introduction port.
Inert gas such as Ar, He, O ₂ , H ₂ or Cl ₂ ,
Fluorine gas, sterilizing gas, etc. are introduced and brought to a predetermined pressure. In this state, the microwave introduction device is operated to inject microwave energy into the vacuum container to generate plasma, thereby performing the required sterilization process.

In addition, since a magnetic field is generated in a vacuum container equipped with a coil or permanent magnet, the residence time of electrons in space is extended due to the effect of the magnetic field, the number of collisions with gas molecules increases, the plasma density increases, and sterilization occurs. It can increase efficiency.

Embodiments Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.

FIG. 1 shows an embodiment of the microwave discharge plasma sterilization apparatus according to the present invention, in which 1 is a vacuum container;
It is provided with an exhaust port 2 connected to a vacuum pump (not shown), a gas introduction port 3 connected to a suitable gas supply source, and a door 4 for putting in and taking out objects to be sterilized. A processing shelf 5 for placing objects to be sterilized is arranged within the vacuum container 1. Further, as shown in the figure, a window 6 made of a dielectric material such as quartz glass or ceramic is provided in a part of the wall of the vacuum vessel 1, and outside of this window 6 is a microwave guide which constitutes a microwave introducing device. A tube 7 is attached. The level of microwave energy introduced into the vacuum vessel 1 via the microwave waveguide 7 can be appropriately set depending on the operating conditions.

Further, a permanent magnet 8 is provided within the vacuum container 1 to generate magnetism.

Another embodiment is shown in FIG. 2, and 9 is a vacuum container, which is equipped with a gas introduction port 10, an exhaust port 11, and a door 12 as in the embodiment shown in FIG. A processing shelf 13 on which items are placed is arranged. Reference numeral 14 denotes a window made of a dielectric material provided on the wall of the vacuum vessel 1. A microwave waveguide 14 is attached to the outside of the window, and a magnetic coil 15 is provided to the outside of the vacuum vessel 9.
In this case, a permanent magnet may be used instead of the magnetic coil 15.

FIG. 3 shows another example of a method for introducing microwave energy into a vacuum container. In FIG. 3, an opening 17 is provided in the wall of the vacuum vessel 16, a connector 18 is attached to the opening 17, an antenna 19 extends from the connector 18 into the vacuum vessel 16, and the connector 18 is connected to a coaxial cable. 20
to a microwave power source (not shown).

When carrying out a sterilization operation using the apparatus of each of the illustrated embodiments configured in this way, first, the objects to be sterilized are placed on the processing shelves 5 and 13 arranged in the vacuum containers 1 and 9. , and evacuate to a predetermined pressure using a vacuum pump. Thereafter, the above-mentioned gas is introduced into the vacuum vessels 1 and 9 through the gas introduction ports 2 and 10, and in the embodiment shown in FIG ^.
The pressure is approximately 1.3×10 ² pa, and in the embodiments shown in FIGS. 1 and 2, the pressure is approximately 1.3×10 ⁻² to 1.3×10 ² pa. In this state, the microwave waveguides 7, 14
or via the coaxial cable 20 to the vacuum vessels 1 and 9.
A predetermined microwave energy is input into the chamber. As a result, plasma is generated in the vacuum containers 1 and 9, and the objects to be sterilized placed on the processing shelves 5 and 13 are sterilized. In this manner, the microwave input is stopped after the scheduled time, and the pressure is returned to atmospheric pressure and the object to be sterilized is taken out. In this way, a series of sterilization operations are performed.

As shown in FIGS. 1 and 2, a permanent magnet 8 and a magnetic coil 15 are used to generate a magnetic field within the vacuum vessels 1 and 9, and the state of the plasma generated inside is controlled. High sterilization efficiency can be obtained.

As an example, O ₂ plasma was generated under a pressure of 0.04 × 10 ² Pa (microwave input at this time was 200 W) using a device with the structure shown in Figure 1, and 10 ⁶ Bacillus subtilis spores were used as a sample. When sterilization was performed using a sample coated on a slide glass, complete sterilization was achieved in just 3 minutes. 20 when the same sample is sterilized using the conventional steam sterilization method.
The conventional electrical discharge sterilization method took 5 minutes. From this, it is recognized that the apparatus according to the present invention is capable of clean sterilization at low temperatures and in a short time.

Effects As explained above, in the present invention, plasma is generated by inputting microwave energy without using electrodes, and the sterilization process is performed thereby. It is possible to eliminate the drawbacks of sterilization methods, ultraviolet sterilization methods, discharge sterilization methods, etc., and efficiently perform clean sterilization without contamination at low temperatures and in a short time.

[Brief explanation of drawings]

FIG. 1 is a schematic sectional view showing an embodiment of the present invention;
FIG. 2 is a schematic sectional view showing another embodiment, and FIG. 3 is a diagram showing an example of microwave introduction means. In the figure, 1, 9: Vacuum container, 2, 10: Gas introduction port, 3, 14: Exhaust port, 5, 13: Processing shelf, 7, 14, 18, 19, 20: Microwave introduction device, 8, 15 : Magnetic device.

Claims (1)

[Claims] 1 Place a processing shelf for objects to be sterilized in a vacuum container equipped with an exhaust port and a gas introduction port connected to an exhaust system, and install a microwave introduction device in the vacuum container to introduce microwaves into the vacuum container. What is claimed is: 1. A microwave discharge plasma sterilization device characterized by being provided with a magnetic device that generates plasma inside the vacuum container and generates a magnetic field that controls the state of the plasma inside the vacuum container.