Classification of ultraviolet rays
1, UVA band, wavelength 320~420nm, also known as long wave black spot effect ultraviolet. It has a strong penetrating power, can penetrate most transparent glass and plastic. More than 98% of the UVA contained in sunlight can penetrate the ozone layer and clouds to reach the Earth's surface, and UVA can reach the dermis of the skin, destroying collagen fibers and tanning our skin. It is often used in worm lamp, ore identification, stage decoration, banknote inspection and so on.
2, UVB band, wavelength 275~320nm, also known as the middle wave erythema effect of ultraviolet. Medium penetration, its short wavelength part will be absorbed by the transparent glass, sunlight contains UVB most absorbed by the ozone layer, only less than 2% of the surface of the Earth. The use of special violet glass and phosphor made, such as ultraviolet health lamp, plant growth lamp.
3, UVC band, wavelength 200~275nm, also known as short-wave sterilization ultraviolet. It has the weakest penetration ability and cannot penetrate most transparent glass and plastic. Sunlight contains shortwave ultraviolet rays that are almost completely absorbed by the ozone layer. Generally used in ultraviolet germicidal lamps.
4, UVD band, wavelength 100~200nm, also known as vacuum ultraviolet.
Principle of sterilization by ultraviolet lamp
The ultraviolet lamps used for sterilization in the laboratory mainly use the UVC band, and the ultraviolet light in this band is mainly obtained by high-pressure mercury lamps, and the mainly produced is 254nm wavelength ultraviolet light.
The bactericidal principle of ultraviolet light is: first, direct irradiation changes the structure of microbial nucleic acid; The second is to convert oxygen in the air into ozone, which has strong oxidation and can effectively kill bacteria.
Note: This part of the ultraviolet light is not able to pass through the glass, the penetration ability is very weak, the cloth on the body, the gloves can be blocked, so do not worry too much about the sterilization ultraviolet lamp in the Laminar Flow Cabinet. If you really worry about it, you can wear long sleeves and pants, with gloves, to prevent exposure to bare skin.
Laminar Flow Cabinet precautions
Q1. Can the fluorescent lamp in the room be turned on when the Laminar Flow Cabinet is opened for ultraviolet sterilization?
A: It is supposed to be impossible to turn on the light, because the light has a resurrection effect, if the light is given during the ultraviolet sterilization process, the survival rate will be greatly improved when the cells are immediately exposed to visible light after ultraviolet irradiation. However, this light repair process is relatively slow, and the ultraviolet has killed most of the bacteria, and a little resurrection will not have much impact.
Q2. Can the ventilation be opened synchronously when the Laminar Flow Cabinet is UV sterilized?
A: If the ultraviolet lamp is turned on simultaneously with the ventilation, although the fan is conducive to extracting bacteria, it is not conducive to the bactericidal effect of the ozone produced by the ultraviolet lamp. Therefore, the best way is to turn on the ultraviolet lamp. to sterilize, wait until 15 minutes to 20 minutes before the experiment to turn on the fan, so that the clean area is clean, and be sure to turn off the ultraviolet germicidal lamp when the staff begins to work, otherwise it will burn the eyes and skin of the staff.
Q3. Is it necessary to light the alcohol burner when UV sterilization is opened on the Laminar Flow Cabinet?
A: Some people may think that since UV lamps have been turned on to sterilize, there is no need to light alcohol burner to sterilize it. In fact, the clean table is not a real aseptic operation, under the premise of correct operation, the alcohol burner can improve the reliability of aseptic operation, this step is very necessary.
Laminar Flow Cabinet use specification
① Prepare before starting:
Check status signs to ensure equipment is in good condition;
Turn on the ultraviolet lamp 30 minutes before use to irradiate the working area;
Open the purifying air 20 minutes before use, and wipe the table clean;
Wipe and disinfect the surface of the tools/articles to be used with alcohol cotton and put them on the work table;
Pull down the glass cover on both sides of the table, and pay attention to the force of both hands to be even.
② Boot:
When operating, turn on the lamp switch and turn off the ultraviolet lamp;
The operating area is laminar flow area, so the working position should not hinder the normal flow of air; Staff should avoid making actions that can cause disruption of air flow;
Operators should wear work clothes.
③ Stop:
After the work is finished, turn off the fan;
Clean machines and workplaces.
