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What are the constraints on the sterilization effect of ultraviolet sterilizers

2023/03/28

The ultraviolet sterilizer uses the optical principle to design a unique inner wall treatment process, so that the interior can maximize the use of ultraviolet rays, and the sterilizing effect is doubled. The ultraviolet sterilizer can effectively kill various bacteria, viruses and other microorganisms, and is easy to operate and maintain. The whole set of equipment occupies a small area, has a large water output, and is very convenient to install, and is deeply loved by people in the industry.

However, while using the ultraviolet sterilizer, it is necessary to understand the factors that restrict the ultraviolet sterilizing effect. I hope it will be helpful to you. 1. The influence of humidity There is no consensus on the influence of humidity on ultraviolet sterilization. When the relative humidity is above 60% to 70%, the killing rate of microorganisms will drop sharply, the most suitable is 40% to 60%, and more than 80% may even have an anti-activation effect.

When the relative humidity increases from 33% to 56%, the bactericidal efficiency can be reduced to the original 1.3. Others believe that the impact of humidity on the sterilization rate may be manifested in three aspects: ① Due to the high relative humidity, the particles in the air increase, which are easy to capture during sampling, and the bactericidal effect is reduced on the surface. ②The increase in particle size weakens radiation penetration into cells, thus reducing the killing effect.

③When the relative humidity is 60% to 70%, the water content of bacteria in the air is 30g, 100g of bacteria, this amount is called the critical water content. Ultraviolet radiation energy transfer can destroy the conjugation relationship of bacterial macromolecules. This effect is likely to occur in bacteria with critical water content and dehydration. Therefore, the sterilization efficiency of ultraviolet rays is generally low under high humidity conditions. The protective effect of inositol and some compounds on microbial aerosol is precisely because they replace the bound water lost by bacteria.

2. The number of microorganisms, the influence of suspended carriers and organic matter. Experiments have shown that the more bacteria that are contaminated, the greater the dose of ultraviolet radiation required. Bacteria attached to dust and suspended in the air are more resistant than bacteria liquid aerosols, because the penetration of ultraviolet rays is very poor, and air dust can absorb ultraviolet rays and reduce the sterilization rate. When the air contains 800-900 cm3 of dust particles When the bactericidal effect can be reduced by 20% to 30%, the presence of peptone, eggs, milk, blood, serum, etc. can enhance the resistance of microorganisms to ultraviolet light, because adding organic solvents to DNA or dimethyl thymine solution can make For base de-stacking, experts have studied the effects of different organic solvents on the formation of thymine dimers, and found that the greater the non-polarity, the smaller the dimerization. 3. Irradiation intensity and irradiation time The lower the irradiation intensity of the ultraviolet lamp, the worse the bactericidal effect. When the intensity is lower than 70Lw.cm2, even if it is irradiated for 60 minutes, the killing rate of bacterial spores cannot meet the qualified requirements.

The irradiation dose of ultraviolet lamp increases with the increase of irradiation intensity. When the irradiation dose is equal, the bactericidal effect of different irradiation intensities is similar 1-3. Therefore, the disinfection technical specification stipulates that the irradiation intensity of the ultraviolet disinfection lamp tube should not be lower than 70Lw.cm2, and when the disinfectant is unknown or when a variety of viruses and bacteria are to be killed, the irradiation dose should not be lower than 100Lws.cm2. The irradiation intensity of the ultraviolet lamp is affected by voltage, temperature, irradiation distance, irradiation angle, etc. At the same time, attention should be paid to the cleanliness and service life of the lamp.

Experiments show that the intensity of the ultraviolet lamp decreases by 15-20Lw.cm2 every time the voltage drops by 10V, and the ultraviolet lamp cannot work when the voltage is below 190V. Under the condition of a voltage of 220V, and the room temperature ranges from 0 to 40°C, the ultraviolet irradiation intensity increases with the increase of room temperature. For example, when the lamp temperature drops from 27°C to 4°C, the output drops by 60% to 80%. When the voltage is 190-240V and the room temperature is 16-35°C, the ultraviolet irradiation intensity has a linear relationship with the voltage and room temperature Y=-325.12+2.014X1+0.72X2.

The relationship between ultraviolet radiation intensity and distance is E=97,72, and the effective distance of ultraviolet radiation is 0.7-2.4m. Outside the vertical line at both ends of the ultraviolet lamp, the ultraviolet intensity attenuates significantly with the increase of the angle, and is 0 near the center line outside the ultraviolet. Therefore, when ultraviolet disinfection is performed, multiple lamps are used at right angles to each other to offset dark areas.

4. Types of microorganisms Various microorganisms have different tolerances to ultraviolet rays. Fungal spores are the most resistant to ultraviolet light, followed by bacterial spores, and the worst are reproductive-type microorganisms. Generally, bacterial spores are 2 to 7 times more resistant than their propagules.

There are also differences in the resistance to ultraviolet light among different strains of the same species, between different cultures of the same species and between different generations. 5. The influence of temperature Most microorganisms (except Micrococcus) are very sensitive to ultraviolet radiation at low temperature, because under this condition, the number of thymine dimers is significantly reduced, and the accumulation of thymine photoproducts will affect microorganisms. repair. And temperature changes also affect the intensity of ultraviolet rays.

Too high or too low temperature will affect the disinfection effect. Generally, the appropriate temperature is 20-40°C7, and some people think that the appropriate temperature is 10-25°C. Poolking is the best swimming pool equipment manufacturer and supplier in China. Poolking exists to provide the highest quality swimming pool equipment while offering competitive pricing..

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