JPS6058671B2 - Sterilization method and sterilization device using accelerated particle irradiation - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a sterilization method and sterilization device using accelerated particle irradiation.

Although various sterilization methods are widely known and practiced, each is associated with significant drawbacks.

Sterilization by boiling cannot sufficiently kill spore bacteria. In the so-called heat sterilization method in which the object to be sterilized is exposed to high-temperature air or high-temperature, high-pressure steam, the object to be sterilized must be heat resistant, and therefore the material of the object to be sterilized is extremely limited. Similar drawbacks exist with sterilization methods using other heating means such as high frequency heating or microwave heating. In the gas sterilization method, in which a sterilizer such as ethylene oxide is turned into a gas and filled into a container containing objects to be sterilized, various conditions such as gas concentration, temperature, humidity, and pressure must be adjusted appropriately to obtain the appropriate sterilization effect. However, this adjustment is troublesome, and furthermore, variations in these conditions can cause large changes in the bactericidal effect. Moreover, it takes a long time to be effective, and even after long hours of work, if the object to be sterilized has a complicated shape, the gas may not penetrate the object sufficiently, resulting in insufficient sterilization. may occur. Furthermore, the disinfectant used in this sterilization method, such as ethylene oxide, is toxic and remains for a long time because it is adsorbed to the object to be sterilized. In the ultraviolet sterilization method in which the object to be sterilized is irradiated with ultraviolet rays, a sterilizing effect can be obtained in a relatively short period of time, but the intensity of the ultraviolet rays is considerably reduced due to dirt on the ultraviolet lamp, reducing the sterilizing effect. Moreover, when the density of bacteria increases to IQ'/c#f or more, the sterilizing effect becomes insufficient due to the shadow effect of the bacteria themselves. An object of the present invention is to provide a new sterilization method that eliminates the drawbacks of the various conventional sterilization methods described above, and a sterilization device suitable for implementing this method. To achieve this objective, the sterilization method according to the present invention ionizes a non-toxic gas, accelerates the ions formed thereby, irradiates the object to be sterilized, and irradiates the object to be sterilized. It is characterized by sterilizing bacteria using irradiation energy. After the ions are neutralized if necessary, the object to be sterilized is irradiated. The sterilizer according to the present invention also includes a support member capable of supporting objects to be sterilized in an airtight sterilization container that is evacuated to a vacuum, and an ion generator configured to introduce non-toxic gas and ionize the gas. An accelerator for accelerating the ions formed by the ionization is arranged between the sterilizer and the sterilizer so that the accelerated ions can irradiate the object to be sterilized in the sterilization container, so that the ions adhere to the object to be sterilized. It is characterized by being able to sterilize bacteria in the air using irradiation energy. In this case, if necessary, a neutralizer is provided to neutralize the ions, which are then irradiated onto the object to be sterilized. Therefore, the sterilization method and sterilization apparatus according to the present invention can be performed using boiling, high-temperature air, high-temperature and high-pressure steam, high-frequency heating,
Since microwave heating, disinfectant gas, ultraviolet rays, etc. are not used at all, sterilization can be achieved without any of the drawbacks of conventional sterilization methods that utilize these.

According to what has been discovered, the sterilizer of the present invention having the above-mentioned features can sterilize objects at low temperatures and in a short time regardless of their shape or material. A sufficient sterilizing effect can be obtained.

In this respect, the present invention achieves extremely effective and harmless sterilization. Embodiments of the sterilization method and sterilization apparatus of the present invention will be described in detail below with reference to the drawings. Sterilization according to this invention as shown in Figure 1! A first embodiment of the device has a sterilization container 1 of airtight construction, in which a support member 3, for example a support stand or a support shelf, for supporting the object to be sterilized, for example a bottle 2, is fixedly arranged, in which the sterilization container 1 is placed. The entrance/exit for the objects to be sterilized provided on the side can be closed airtight by a door 4 hinged to the outer surface of the sterilization container.

In order to evacuate and maintain the inside of the sterilization container 1 to a vacuum of, for example, 1.times.10@-5 Torr or less, the sterilization container 1 is connected to a vacuum evacuation system 5. This vacuum exhaust system 5 includes, for example, an oil diffusion pump 8 connected to a first exhaust port 6 of the sterilization container 1 via an on-off valve 7, and an oil diffusion pump 8 connected to the exhaust side of the oil diffusion pump 8 via a switching valve 9. Rotary vacuum pump 10 and second sterilization container 1
It is composed of a rough piping 12 connecting the exhaust port 11 and the switching valve 9, and the like. The detailed construction and method of operation of such a vacuum evacuation system 5 are well known to those skilled in the art. Sterilization container 1
furthermore has a clean air inlet with an air inlet valve 13. The sterilization container 1 has a large upper opening 14, which is connected to a lower end opening 16 of an accelerated particle generating system housing 15, which is configured in a gas-tight manner.

Inside the housing 15, from the top, there are an ion generator 17,
An accelerator 18 and a neutralizer 19 are arranged. Note that some of these may be placed inside the sterilization container 1.
The ion generator 17 serves to ionize a non-toxic gas, such as an inert gas such as argon, or oxygen, introduced from a gas inlet 20 provided at the upper part of the housing 15, and is used, for example, as an RF ion source or a hot cathode. It consists of a type ion source, etc.

The accelerator 18 serves to accelerate the ions generated by the ion generator 17, or more specifically, to accelerate and extract them, and is usually constituted by electrodes. The neutralizer 19 is constituted by a thermionic emission filament or a charge exchange cell, and functions to neutralize the ions accelerated by the accelerator 18. The above-mentioned ion generator 17 and accelerator 18
An example of the neutralizer 19 will be described with reference to FIG. 2. An anode 22 is arranged around a hot filament 21 which is arranged at the upper center and to which heating direct current is applied.
Around the anode 22 is an electromagnet 2 to which excitation direct current is applied.
Further, a cathode grid 24 to which a negative voltage is applied with respect to the anode 22 is arranged below the anode 22 .

A glow discharge can be generated in the space surrounded by these members 21, 22, 23, and 24, thereby achieving ionization. Therefore, these members 21
, 22, 23 and 24 constitute the ion generator 17. A positive voltage of, for example, 0 to 1000 V is applied to the cathode grid 24 with respect to the grounded support member 3, and a drawer grid 25 disposed below the cathode grid 24 is applied with a positive voltage of, for example, -100 to - with respect to the grounded support member 3. A negative voltage of 200 V is applied, and these gratings 24 and 25 constitute an accelerator 18 that accelerates and extracts ions. A neutralizing filament 26 is disposed below the extraction grid 25 and serves to neutralize the ions constituting the neutralizer 19. A heating direct current is applied to this filament 26, and its negative terminal is grounded. A repeller 27 is arranged around the space between the extraction grid 25 and the neutralizing filament 26, which is applied with a negative voltage with respect to ground.
28 indicates a power source.

When sterilizing is performed using the sterilizer shown in FIGS. 1 and 2, the door 4 is first opened and the object 2 to be sterilized is placed on the support member 3. After the door 4 is closed, the inside of the sterilization container 1 and the housing 15 are evacuated to a vacuum of, for example, 1.times.10@-5 Torr or less by the vacuum evacuation system 5. The method of operating such evacuation is well known and will not be described in detail. Next, a non-toxic gas as described above is introduced from the gas inlet 20 into the sterilization container 1 and the housing 15, so that the pressure of the gas therein is between 1×10 −5 and 1×1.
It is adjusted to a value such as 0-4 torr. This pressure is selected such that the distance between the ion generator 17 and the object 2 to be sterilized is within the mean free path of this gas. Then power supply 28
When current is supplied and voltage is applied to the members 21 to 27 by the The sexual gas molecules irradiate the object 2 to be sterilized,
Bacteria attached to the object to be sterilized are sterilized by the energy of the irradiation. After the sterilization work is completed, the power supply 28 is turned off, clean air is introduced into the sterilization container 1 and the housing 15 through the air introduction port equipped with the air introduction valve 13, and the object 2 to be sterilized is taken out from the sterilization container 1. Ru. When storing the object 2 to be sterilized without removing it, aseptic storage is achieved by keeping the inside of the sterilization container 1 and housing 15 in a vacuum state. It is desirable that the support member 3 be cooled by water cooling or the like during the irradiation operation. The time required for the above-mentioned sterilization is as short as a few minutes, the sterilization operation is carried out safely because non-toxic gases are used, and the temperature of the object to be sterilized does not substantially rise. Furthermore, by adjusting the accelerating voltage, sterilization suitable for the material and shape of the object to be sterilized can be achieved without damaging the object. In the sterilization method using the above-mentioned sterilizer of the present invention, the results of a test using a glass plate coated with Bacillus subtilis spores at a density of 1 Cf'/Clt as the object to be sterilized are shown in FIG. At this time, argon is used as the gas, and this
and a pressure of 5 x 10-5 Torr was maintained within the housing 15. The distance between the object to be sterilized 2 and the ion generator 17 was 25 cm, which was less than the mean free path of argon at this pressure, and 1000 cm was used as the accelerating voltage. The relationship between the sterilization treatment time and the number of viable bacteria is as shown in FIG. 3. In the graph of FIG. 3, the horizontal axis represents the treatment time in minutes, and the vertical axis represents the number of viable bacteria in cells/d. As is clear from this graph, substantially complete sterilization was achieved in about 5 minutes. FIG. 4 shows an embodiment of a sterilizer suitable for semi-continuous sterilization, in which components identical or similar to those shown in FIG. 1 are designated by the same reference numerals.

In this case, the sterilization container 1 is connected on its right side to an airtight passage 31 on the side of the storage room for sterilized items via an airtight gate 30, and on the left side is connected to an airtight passage 33 on the side of the packaging system for sterilized items via an airtight gate 32. Ru. The gas-tight passages 31 and 33 are connected to their own suitable evacuation systems 34 and 35. In this sterilizer, for example, inside the sterilization container 1 (and housing 15), inside the airtight passage 31, and inside the airtight passage 33.
With the inside evacuated to a vacuum, the airtight gate 30 is opened and the object 2 to be sterilized is transferred from the airtight passage 31 into the sterilization container 1 by a suitable transport means 36. After closing the airtight gate 30 (at this time also closing the airtight gate 32), sterilization is accomplished in the same manner as described with respect to FIGS. 1 and 2. After the sterilization work is completed, the airtight gate 32 is opened and the sterilized object 2 is transferred from the sterilization container 1 into the airtight passage 33 by a suitable transport means 37, and then the airtight gate 32 is closed. It will be done. Semi-continuous sterilization is achieved by repeating the operations described above. In addition,
In the embodiment shown in FIGS. 1 and 4, the neutralizer 1
9 may be omitted, in which case the accelerated ions are directly irradiated onto the object to be sterilized.

[Brief explanation of the drawing]

Fig. 1 is an illustrative diagram of a first embodiment of the sterilizer according to the present invention, and Fig. 2 schematically shows the arrangement and circuit of the ion generator, accelerator, and neutralizer employed in the sterilizer of Fig. 1. FIG. 3 is a graph showing the sterilizing effect using the device shown in FIG. 1, and FIG. 4 is an illustrative diagram of a second embodiment of the sterilizing device according to the present invention. In the drawings, 1 is a sterilization container, 2 is an object to be sterilized, 3 is a support member, 17 is an ion generator, 18 is an accelerator, and 19 is a neutralizer.

Claims (1)

[Claims] 1. A non-toxic gas is ionized, the ions formed thereby are accelerated, and the object to be sterilized is irradiated with the ions, and the bacteria attached to the object to be sterilized are destroyed by the energy of the irradiation. A sterilization method using accelerated particle irradiation, characterized by sterilization by irradiation with accelerated particles. 2. The sterilization method according to claim 1, wherein the accelerated ions are neutralized and then irradiated onto the object to be sterilized. 3. A support member capable of supporting objects to be sterilized in an airtight sterilization container that can be evacuated, and an ion generator configured to introduce a non-toxic gas and ionize this gas. An accelerator that accelerates the ions formed by the sterilization is placed so that the object to be sterilized in the sterilization container can be irradiated with the accelerated ions, and the bacteria adhering to the object to be sterilized are destroyed by the energy of the irradiation. A sterilization device using accelerated particle irradiation, which is characterized by being able to sterilize by irradiating particles. 4. A sterilizer according to claim 3, which includes a neutralizer that neutralizes accelerated ions, and irradiates objects to be sterilized with neutral particles generated by the neutralizer. .