Factors influencing disinfection effect of ultraviolet disinfection lamp
Time:2022-06-13
Views:111
Ultraviolet disinfection lamp is also called ultraviolet sterilization lamp and ultraviolet fluorescent lamp. The utility model relates to a lamp which uses the sterilization effect of ultraviolet rays to sterilize. The ultraviolet disinfection lamp radiates ultraviolet light with a wavelength of 253.7nm. This band of ultraviolet has the strongest sterilization ability and can be used for disinfection and sterilization of water, air, clothing, etc. UV disinfection lamps commonly used in pig farms are 15W, 20W, 30W and 40W, with a voltage of 220V. They are mainly used for disinfection and sterilization of personnel, and are generally installed in disinfection dressing rooms, veterinary rooms and laboratories. So what are the factors that affect the disinfection effect of ultraviolet disinfection lamp? The following is a compilation of photobiology to popularize this knowledge for everyone.
1. influence of voltage
The radiation intensity of the UV light source is obviously affected by the voltage. When the voltage of the same UV light source is insufficient, the radiation intensity decreases a lot. Radiation intensity of 30W straight tube quartz ultraviolet lamp under different voltages,
It can be calculated by the following formula:
Y=1.287X−177.87
Where, Y -- theoretical value of ultraviolet intensity, unit: μ W/cm2;
X - voltage, unit: v.
If the strength is 100 at 220V μ W/cm2 as the acceptance control point of the new lamp, the control line for measuring the radiation intensity of the new ultraviolet lamp under different voltages is
Y= 1.287X-183.14
If the strength at 220V is 70 μ W/cm2 as the control point for replacing the old lamp, the radiation intensity control line measured under different voltages is
Y= 1. 287X-213.14
2. influence of distance
Generally speaking, the radiation intensity of ultraviolet lamp is inversely proportional to the square of distance. Radiation intensity y of 30W low pressure mercury hot cathode straight tube lamp ˆ It decreases with the increase of distance x from the lamp, and the relationship between them is exponential.
Its exponential curve equation is
Y ˆ= 102.885? 9-0.760? 8x
According to this formula, the radiation intensity of ultraviolet lamp at different distances can be calculated.
3. influence of temperature
The effect of temperature on the efficacy of ultraviolet disinfection is realized by affecting the radiation intensity of ultraviolet light source. Generally speaking, the ultraviolet light source radiates the strongest sterilization ultraviolet at 40 ° C. When the temperature decreases, the output of the ultraviolet lamp decreases; When the temperature is higher than 42 ° C, the ultraviolet absorption of radiation increases and the output decreases. Therefore, too high and too low temperature are unfavorable to ultraviolet disinfection. However, some germicidal tests have proved that the temperature has little effect on the germicidal efficacy of ultraviolet radiation in the range of 5 ~ 37 ° C. At low temperatures, microorganisms become more sensitive to ultraviolet light.
4. influence of relative humidity
When disinfecting the air, the relative humidity also has an effect on the disinfection effect. When the RH is too high, the number of small water droplets in the air increases, which can block ultraviolet rays. Therefore, when ultraviolet rays are required to disinfect the air, the relative humidity should be below 60%. When disinfecting the surface, if the irradiated surface is far from the light source, the moisture particles in the air will also affect the disinfection effect.
5. effect of irradiation time
There is an exponential relationship between the disinfection effect of ultraviolet and the irradiation dose, which can be expressed as
N/No=e-KIt
Where, N0 - bacterial count before irradiation;
N -- number of bacteria after irradiation for a certain time;
T - irradiation time;
I - irradiation intensity;
K - constant.
From the above formula, it can be seen that increasing the irradiation time t or increasing the irradiation intensity can increase the disinfection effect, and the irradiation dose is the product of the irradiation intensity | and the irradiation time. Therefore, to make the killing rate reach a certain level, it is necessary to ensure sufficient irradiation dose. When the radiation intensity of the ultraviolet light source meets the requirements (greater than 40 μ W/cm2), the required irradiation dose can be achieved by adjusting the irradiation time.
6. impact of organic matter protection
When microorganisms are protected by organic substances, it is necessary to increase the irradiation dose, because organic substances can affect the penetration of ultraviolet rays into microorganisms, and the group will absorb ultraviolet rays.
7. influence of microbial species and quantity
Different microorganisms have different levels of resistance to ultraviolet light, so the irradiation dose should be determined according to the types of microorganisms killed. Sterilized articles The more contaminated microorganisms, the worse the disinfection effect. Therefore, before disinfection, it is necessary to have a better understanding of the types and quantities of contaminated microorganisms on the disinfection object in order to determine the irradiation dose.
