Ultraviolet disinfection technology Principle 2013-3-7

Ultraviolet disinfection technology principle

1, all kinds of electromagnetic wave wavelength and classification

Ultraviolet light is one of the many electromagnetic wave, all kinds of electromagnetic wave wavelength see table below:

Serial number
Electromagnetic wave name
wavelength

1
Radio waves
1000000 ~ 10 mm

2
Magnetic wave
1 ~ 100 mm

3
infrared
800 ~ 10000 nm

4
Visible light
380 ~ 800 nm

5
ultraviolet
10 ~ 400 nm

A wave (near wave)
320 ~ 400 nm

B wave (medium wave)
275 ~ 320 nm

C wave (far wave)
200 ~ 275 nm

Vacuum ultraviolet
10 ~ 200 nm

6
X - ray
0.01 ~ 100 nm

7
Y - ray
0.01 nm or less

2. Electromagnetic wave propagation mode

In the same medium transmitted in straight line, when the medium change, will produce the reflection and refraction.

3. Reflection and focus

(1) when the incident ultraviolet communication media change, uv in contact to another medium moment, can produce reflections and refractions.

(2) reflection: it is in the same propagation medium; According to the principle of reflection, the Angle of reflection and Angle of incidence direction instead, equal. The reflectivity of magnesia the highest to 80 ~ 90%, oxidation polishing aluminum reflectivity for 65 ~ 75%, stainless steel plate reflectivity for 70 ~ 80%.

(3) refraction: it's in the different propagation medium; According to the propagation medium is different, the size of the refraction Angle are not the same. Gas refraction performance is good, liquid refraction performance medium, solid refraction performance is poor, transparent body refraction is higher.

4. No visible

The wavelength of visible light in 380 ~ 800 nm, and we use uv wavelength in 100 ~ 380 nm, is can't see.

Ultraviolet sterilization effect

1. Sterilization band: ultraviolet sterilization is in commonly 200 ~ 280 nm, the strongest section for 240 ~ 280 nm bactericidal effect. The most obvious band is 253.7 nm.

2. Sterilization and dose

Results show that: uv water microbial kill dose (μ w.s/cm2)

Serial number
Microbial name
Different killing rate of radiation intensity

90%
99%
99.9%
100%

1
Bacillus subtilis spore
10000
20000
40000

2
Escherichia coli
3000
6000
12000

3
Staphylococcus aureus
3000
6000
12000

4
Salmonella typhi
4000
8000
16000

5
Corynebacterium diphtheriae
5000
10000
20000

6
Mycobacterium tuberculosis
5100
10000
20000

7
Aspergillus Niger spore
150000
300000
600000

and
Influenza virus
1000
2000
≦ 5000
6600

9
Tetanus bacillus
3500
7000
16700
22000

ten
Hemolytic streptococcus
1000
2000
4000
5500

11
Escherichia coli phage
1000
2000
5000
6600

Microbial factors

1. The microbes to ultraviolet sensitivity:

High type microorganisms, such as radiation resistant micrococcus, bacillus subtilis spore - resistance ability;

The resistant microorganisms, such as mouse salmonella typhi, yeast, milk streptococcus, the resistance of the medium;

Low resistance microorganisms, such as escherichia coli, staphylococcus aureus, vaccinia virus - weak ability to resist.

2. Microbial quantity:

The greater the pollution load, ultraviolet radiation sterilization effect is poor.

3. Organic protection:

Bacteria in the dirt, ultraviolet radiation sterilization effect is reduced. Dirt is bacteria growth, reproduction and the damage by organic environment.

Sterilization mechanism

1. Effect on nucleic acid:

DNA, forming thymine dimer, TT

RNA, forming a pyrimidine dimer, uu

2. Effect on protein:

Can make the protein denaturation, enzyme inactivation.

Uv technology application in water treatment

Uv technology in the world is increasingly widely used in all kinds of water treatment system - Adam Donnellan

Use ultraviolet light kill aquatic infectious germs advantages has been widely confirmed. In fact, the industry is the first to use the one of the pioneers of the technology. Today, almost all of the industry will be uv technology is applied to water treatment system, including food and beverage industry, the pharmaceutical industry, cosmetics industry, health care products industry, manufacturing, high technology industry and so on. The sterilization is uv technology in water and waste water is mainly used in the field of. Meanwhile, the industry will also this technology application in many other aspects, including eliminate ozone, reduce the total organic carbon (TOC), liquid sugar disinfection, degradation of chlorine, surface and air and cooling tower disinfection, etc. This paper will use some of the ultraviolet ray in industry are briefly.

sterilization

Ultraviolet radiation sterilization was mainly used for the 254 nm wavelength of ultraviolet light. The wavelength of ultraviolet light, even in trace amounts of ultraviolet ray projection doses, also can destroy a cell life core - DNA, so stop cell regeneration, the loss of regeneration ability become harmless bacteria, so as to achieve the effect of sterilization. Like all other uv application skill