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How does a UV light sanitizer work?

Views:0     Author:Anny     Publish Time: 2021-03-04      Origin:https://www.suntechleds.com/

UV disinfection

With the outbreak of COVID-19, UV sanitizer has once again attracted the attention of the whole society. 1878, Arthur Downes and Thomas P. Blunt have published a paper explaining how to kill bacteria exposed to shortwave light. In medicine, ultraviolet light has been used as a mutagen to modify the DNA of cancer cells to treat diseases for more than 100 years. The history of using ultraviolet rays to disinfect water can also be traced back to the 1990s.

Before we talk about the working principle of UV light sanitizer, it is necessary to figure out what is UV light. UV light is electromagnetic radiation with a wavelength from 10nm to 400nm. The light between 200nm to 300nm can be used as a sanitizer to inactivate microorganisms such as bacteria, viruses, and protozoa. UVC is a light with a wavelength range of 200 to 280nm, it cannot reach the ground they cannot pass through the ozone layer. But UVC light has multiple functions like sterilization, organic decomposition, photopolymerization, and sensing.UV light at 254nm has the best germicidal effect against microorganisms.

According to reports, a joint study between Japan's Kobe University and Japanese LED component manufacturer Ushio shows that deep UV sanitizer light with a wavelength of 222nm is harmless to human skin and eyes. Columbia University has also carried out related research, preliminary results show that far UVC with a wavelength of 222nm cannot penetrate the skin surface or eyes, so it is safe for the human body, and it can also be used for sanitizing.


Can UV Sanitizer Light be used for Preventing Coronavirus?

With the continuous spread of the new coronavirus, more people are beginning to pay attention to whether UV light sterilization can be used to prevent the new coronavirus. The FDA has studied this problem. The study shows that the efficacy of UVA and UVB irradiation is lower than that of UVC. So UVC irradiation disinfection is popular and commonly used worldwide now.

Before, researchers published a paper about 222nm irradiation inactivates airborne human coronaviruses on Nature. The results of this study showing that UVC lights can kill at least 2 types of coronaviruses. 222 nm UVC light disinfection is will not do harm to human skin and eyes, and it is a safe and healthy method for protecting against the COVID-2.

UVA UVB UVC wavelength

Next, let's see what factors can affect the effects of UV sterilization.

The effectiveness of disinfecting UV light depends on the time the microorganisms are exposed to ultraviolet rays, the intensity and wavelength of ultraviolet radiation. The longer the illumination time, the more accumulated light, and the better sterilization effect will be achieved. Therefore, to sterilize in a short time needs strong UV lights. In addition, UV disinfection is called line-of-sight technology. Therefore, if anything blocks the UV sanitizing lights, including dirt, stains, and anything that casts shadows, then those "shaded or protected" areas will not be disinfected.


What pros&cons of UV LED lights sterilization?

Pros:

1. Production process without chemical substances, except for emitting ultraviolet rays, no substances produced.

2. Does not produce carcinogenic disinfection by-products.

3. High efficiency in inactivating a variety of microorganisms (including the chlorine-resistant pathogens Cryptosporidium and Giardia).

4. Can be used in combination with oxidants (such as hydrogen peroxide) to decompose and destroy chemical pollutants in the water.

5. Long lifespan and energy saving.


Cons:

Ultraviolet lights are harmful to the human skin and eyes (except 222nm UVC).

Once the skin is irradiated by ultraviolet light, redness, swelling, itching, and scaling may occur in mild cases, and it may even cause skin cancer in severe cases. At the same time, ultraviolet light is also the "invisible killer" of the eye. Ultraviolet light can damage the epithelial cells of the cornea. If exposed to ultraviolet light for more than two hours, different degrees of foreign body sensation will appear. In severe cases, there will be tingling, tearing and even eye spasms. Blurred vision and other phenomena can cause conjunctivitis and keratitis, and long-term exposure can also cause cataracts. Therefore, pay attention to safety when using UV disinfection.

Cell structure

How does UV light kill bacteria:

UV inactivates microorganisms by destroying nucleic acids. Mainly 254 nm UVC cell RNA and DNA absorption. The absorption of ultraviolet energy will form new bonds between adjacent nucleotides, thereby forming double bonds or dimers. Dimerization of adjacent molecules (especially thymine) is the most common photochemical damage. The formation of large amounts of thymine dimers in the DNA of bacteria and viruses prevent replication.


Our Best UVC Light Sanitizer Introduction:

222nm far UVC excimer module:

222nm excimer module

As mentioned above, research reports on the FDA and Nature show that 222nm is harmless to the human body. Our far UV-C excimer lamp has a high-quality narrowband filter to ensure the light emitted is about 222nm. And there is a reflector on the back of the tube to strengthen the irradiation power for high efficient sterilization. A 20W far UV-C excimer can reach 3000μw/cm²output power within 3 seconds. If you are interested in this product, welcome to contact us for further details.

UVC LED strip:

30LED 60degrees UVC LED strip.jpg

Due to the limitation of LED conversion efficiency, it's hard to find high-power UVC LED products, and usually, there needs to install a heat sink for high power UVC LED products. This is not convenient to use. However, this 30LEDs/m UVC strip adopts 20mw LED chip and has added 60 degrees quartz glass, whose irradiation power is times of the ordinary 5mw chips 120 degrees UVC LED strip. And there is tape on the back of the strip which is easy to install to any place needed for surface disinfection. Please Click Here to check the details.


This video shows how do we test the UVC LED strip: