RU2043120C1 - Method for sterilizing articles and materials - Google Patents

Abstract

FIELD: medicine. SUBSTANCE: method involves putting articles in hermetically sealed vessel, evacuating the vessel down to a pressure of 1.0-1,0...10^-3 mm of Hg column to create plasma by means of excitation of the gas discharge by applying alternating electromagnetic field between electrodes embracing the vessel at 1-100 MHz frequency and specific power of 0,05...0,5 Wt/cm ³. EFFECT: enhanced effectiveness in sterilizing materials for food processing. 1 dwg, 1 tbl

Description

 The invention relates to sterilization techniques and can be used in various fields of the national economy, mainly in medicine.

 A known method of sterilization, in which a high-frequency discharge in an atmosphere of hydrogen peroxide is excited inside an evacuated vessel using an inductor. The sterilization process by this method usually takes a long time and requires a special chemically active gas for its implementation.

 The closest is a method that includes placing a sterilized object in a sealed vessel, evacuating the vessel and creating plasma in it by exciting a gas discharge by applying microwave energy. The discharge is excited in the atmosphere of residual gases without any additives, however, sterilization is quite effective even at short exposure times of the object in a plasma medium. At the same time, the use of microwave energy (microwave ovens operate at frequencies of ≈2500 MHz according to US standards) is associated with technical difficulties in providing special equipment that requires an increased degree of protection from microwave fields. This complicates the implementation of the method and limits its mass distribution.

 The aim of the invention is to simplify the method of sterilization by switching to discharge modes, which are implemented technically by simpler means.

The essence of the method lies in the fact that, unlike the prototype, a gas discharge is excited between the electrodes enclosing the vessel. In this case, the vessel is evacuated to a pressure of 1.0.10 ^-3 mm Hg. and the field frequency is selected in the range of 1.100 MHz with a specific power input of 0.05-0.5 W / cm ³ .

 The drawing shows a diagram of a device that implements the proposed method.

 The device includes a glass (dielectric) tube 1 (or a vessel of a different shape), which is hermetically closed by a tube 2 with an opening for a vacuum pipe 3 connecting the tube with the pumping means 4. From the outside, the tube is covered by two electrodes 5 made of thin metal strips and connected to the symmetric output of the high-frequency generator 6. Sterilized samples (products) are located or fixed inside the tube (with the tube being not horizontal);

 The order of implementation of the method is similar to the prototype.

The differences of the proposed method lie in the selection of new modes of operations that are experimentally discovered for a high-frequency gas discharge of a capacitive type. In this case, the capacitive discharge is excited in a simpler way, namely by means of electrodes covering the vessel, which are structurally simpler than the specially shaped inductor used in the prototype. The range of selected pressures is determined by the fact that with an increase in pressure above 1.0 mm Hg it is difficult to ignite a glow discharge in a vessel, and at pressures below 10 ^-3 mm Hg the level of high-frequency plasma concentration (ion and electron density) decreases noticeably, which leads to a decrease in the effect of charged particles on the workpiece.

Frequencies are selected on the basis of stable ignition and combustion of the discharge at relatively low voltages of 10.10 ² V / cm (lower limit) and restrictions on the complexity of the equipment and the need for protection (upper limit). The limits of the input power from below are also limited by the stability of the discharge, and above by the temperature and plasma concentration and, therefore, the permissible temperature of heating the vessel and samples.

 Studies have shown that the processing time when exposed to plasma on the product has no significant effect. Depending on the material of the microorganism carrier, it is 5.15 min and can be reduced due to the specific energy input. Optimal modes within the indicated ranges of variation of the discharge parameters were not found.

PRI me R. A standard test tube with a diameter of 12 mm was used for the device. The electrodes were made of copper foil 0.3 mm thick in the form of strips 10 mm wide. The distance between the electrodes was 20.100 mm. The generator was built according to the standard scheme on electronic tubes of the GU 50 type and had an operating frequency of 28 MHz, corresponding to the matched load of the electrodes. The density of the input power was about 0.4 W / cm ³ (in absolute terms ≈30 W). Microbiological materials prepared and processed by the All-Russian Research Institute of Preventive Toxicology and Disinfection were used as samples. Studies were conducted using a test culture of the microorganism you. subtilis 7, applied to test carriers made of glass, metal, cambric, rubber (5 types) of plastic (2 types).

Processing of the samples was performed at a pressure 5˙10 ^-2 mmHg The results are presented in the table.

 There is a 100% death of the test culture microorganisms on glass, metal with a 5-minute treatment, on a cambric and silicone rubber at a 10-minute treatment. On other materials, the effect manifests itself to varying degrees.

 Note: in the above example, the research protocol of the laboratory of problems of sterilization of medical devices of the specified VNII was used.

 The proposed method is simple to implement, accessible to paramedical or technical personnel, does not require expensive equipment and special protection and can be widely used in various fields. The economic effect of its use can be assessed at the design stage of specific plants, taking into account their required number.

Claims (1)

METHOD OF STERILIZATION OF PRODUCTS AND MATERIALS, including placement in a sealed vessel, evacuation of a vessel, creation of a plasma vessel by excitation of a gas discharge by an alternating electromagnetic field and exposure of objects in a plasma medium, characterized in that, in order to simplify the sterilization process, the vacuum is carried out to a pressure of 1, 0 10 ^{- 3} mm RT. Art. and a gas discharge is excited between the electrodes enclosing the vessel at a field frequency of 1 100 MHz and a specific power input of 0.05 0.5 W / cm ³ .

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