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Working principle of sterilizer


Thermal sterilization

The thermal sterilization method is to use high temperature to coagulate or denature the bacterial protein, inactivate the enzyme, hinder metabolism, and cause bacterial death. Thermal sterilization includes moist heat sterilization and dry heat sterilization. Damp and heat can coagulate and deform the bacterial protein; Dry heat can oxidize, denature, carbonize bacterial proteins and concentrate electrolytes to cause cell death. Thermal sterilization is convenient, effective and non-toxic, and is the main sterilization method used by the hospital disinfection supply center. The pressure steam sterilization method is the preferred sterilization method for humidity and heat-resistant medical devices.

The pressure steam sterilization adopts the damp heat sterilization method. At the same temperature, the sterilization effect of damp heat is better than that of dry heat. There are the following reasons:

The temperature required for protein coagulation is related to its water content. The higher the water content, the lower the temperature required for coagulation. The bacterial protein during moist heat sterilization can absorb water, so it is easier to solidify than in dry hot air at the same temperature.

In the process of damp heat sterilization, the steam gives off a large amount of latent heat, which further increases the temperature. At the same temperature, the time required for damp heat sterilization is shorter than that for dry heat sterilization.

The penetration of humid and hot gas is stronger than that of dry and hot gas, so the effect of humid and hot gas is better than that of dry and hot gas. High pressure steam can kill all microorganisms, even bacterial spores, fungal spores and other high-temperature resistant individuals. The steam temperature of sterilization increases with the increase of steam pressure. By increasing the steam pressure, the sterilization time can be greatly shortened. Therefore, it is the most effective and widely used sterilization method.

Low temperature sterilization

The low-temperature sterilization method is a method that uses chemical sterilization agents to kill pathogenic microorganisms. The temperature required for sterilization of chemical agents is relatively low, which is usually called low-temperature sterilization method or chemical sterilization method. The chemical disinfectant used for low-temperature sterilization can kill all microorganisms and reach the sterilization guarantee level. Such chemical agents with sterilization effect include formaldehyde, glutaraldehyde, ethylene oxide, peracetic acid, etc. Chemical sterilization is used for the sterilization of instruments that cannot withstand high temperature and damp heat.

Common low-temperature sterilization methods include hydrogen peroxide plasma low-temperature sterilization, ethylene oxide sterilization, low-temperature formaldehyde steam sterilization, etc.

1. Hydrogen peroxide plasma low temperature sterilization

The article is sterilized after the hydrogen peroxide liquid disperses into a gas state, and the second stage sterilization is performed by the generated plasma. The plasma process can also accelerate and thoroughly decompose the residue of hydrogen peroxide gas on instruments and packaging materials. The plasma sterilization method is characterized by rapid action, reliable sterilization, low action temperature, cleaning and no toxic residue. Applicable to endoscopes, heat-resistant equipment, various metal instruments, glass and other items; It can absorb moisture and gas.

2. Ethylene oxide sterilization

Ethylene oxide is a colorless gas with a smell similar to that of ether. It is tasteless at low concentration. It has strong gas permeability, can penetrate cellophane, polyethylene or polyvinyl chloride film, etc., and has non-specific alkylation on the protein, DNA and RNA of microorganisms, so that they lose the basic reaction group of metabolism and are killed. It has strong bactericidal power, wide killing range, reliable sterilization effect, and little damage to sterilized articles.