Lampes UV - Applications
Principes Tech. 
TECHNICAL CONCEPTS

UVC ACTION   
  

LightSources & LightTech low-pressure, mercury-arc germicidal lamps are specially designed to produce the highest amounts of UV radiation - where 90% of energy is typically generated at 254nm. This radiation is very close to the peak of the germicidal effectiveness curve of 265nm, the most lethal wavelength to microorganisms.

What are these ultraviolet rays applicable to disinfection?  
The ultraviolet rays are of the same family as the rays creating our "Visible" light. This "family" is the electromagnetic radiation. These rays are classified according to their wavelength, the unit of measure is the meter, or nanometer as one of its multiples (nm symbol). 
The electromagnetic radiation 

Visible Light
 
The visible region that we perceive as light, it’s in the wavelength from 400nm to 800nm. It’s decomposed in wavelengths band that we see as "Colors of the Rainbow" which we can observe after the sunshine period following a stormy rain.
Non-visible light 
Along both sides of the spectre of visible light is:  
Before the red: the Infrared (which heat) 
Beyond violet: Ultraviolet (which destroy) 

The Ultraviolet Rays also called "UV" 
There are three types of UV radiation classified according to their wavelengths (400 à 100 nm), as follow:

UVA (400 to 315 nm)  
The principal action of UVA is the immediate tanning effect. They are often applied in the tanning equipments and medical applications as psoriasis.
UVB (315 to 280 nm) 
UVB can favor the production of vitamin D and is used for the antirachitic applications. They have other uses, as in the systems of in-depth polymerization of adhesives.
UVC (280 to 100 nm) 
It is between 250 and 270 nm where we can find the peak of germicide efficiency. The lamps called "GERMICIDES" emits in 253.7 nm. 
The wavelength in 185 nm is "ozone maker" from the oxygen.  

UVC SOURCES

World-wide Expertise

The UVC germicide effect, studied for more than 70 years has been performed from the research of various processes producing radiation in 253.7 nm.

Fluorescent" tubes function is identical to the “Mercury” tubes used by ERIES® for this process.
These lamps can be different kinds, but mostly:
  • Low-pressure mercury-arc 
  • Medium-pressure mercury-arc 
  • High-pressure mercury-arc. 
They differ in the in UVC energy efficiency compared with the total electric power
  • 30 % Low-pressure lamps 
  • 10 to 20 % Medium-pressure lamps 
  • 5 to 6 % High-pressure lamps   

The lamps
(commonly known as tubes) 


The lamp consists in a quartz tube and an electrode in each extremity. After the initiating the electric arc between 2 electrodes, the "gas" which is by way the vapor of mercury is ionized by the electrical current. The wavelength of the ionized mercury is situated in 253.7 nm, very close to the peak of optimal absorption of microorganisms between 250nm and 270 nm.

QUARTZ GERMICIDAL LAMPS 

The lamp body is made en quartz.

There are several types that define the emission or the filtration of different wavelengths. One of these qualities of quartz filters the rays below 254 nm so forbidding the passage of 185 nm. These lamps are called low-ozone and they are considered only as germicides. Another quartz quality also allows rays in 185 nm to pass. These lamps are called High-Ozone and they are considered as "germicides" adding an "oxidizing effect" (used for the treatment of the smells, in particular). 
 

 
Standard Lamps

The type of fused quartz used to make the body of the germicidal lamp determines the emission of the wavelength of the UV energy. “Low ozone” generating lamps transmit up to 90% of their energy at the 254nm wavelength. Ozone generating lamps are produced using clear fused quartz which allows for the transmission of energy at both 185nm and 254nm wavelengths.


High Output (HO) Lamps 

High Output (HO) lamps yield up to 66% more UV output when compared to standard lamps of the same length. HO lamps offer system designers unique opportunities to decrease the number of lamps required without compromising functionality of the system. This has the added potential benefits of reduced system footprint, increased efficiency and/ or increased system capacity. HO lamps are produced and are available in the same configurations of standard lamps. Custom lengths and configurations may also be produced to the customer’s specific requirements.

Lampes Amalgam 

Our fabricant Light Sources provide the widest range of high-quality spot and pellet amalgam lamps in the industry today. The low pressure amalgam lamps function with equal efficiency in both horizontal and vertical operation. Amalgam lamps yield up to three times the UVC output over standard lamps of the same length.

ERIES® benefits from more than 20 years of research and development in this domain. The technological advantage offered by said lamps "Amalgam" needed to associate the electronics of the same level. The power supply qualified for this type o lamps offers the possibility of reporting in local and remote about the information of right running of lamps.

ENERGY AND DOSES

UVC Energy 
Every point of a switched on UVC lamp emits a radiation which the intensity is expressed in µw / cm ² and which decreases according to the distance regarding the source. Thus, it will be necessary to look for the lamps layout to have radiation optimized and the most homogeneous possible on the surface treated.
Opacity 
It is important to know that the UVC does not cross fluids or transparent materials as visible light does. When they are used for the liquids treatment (water in particular) the calculations always have to take into account the coefficient of appropriate transmissibility to every fluid (this coefficient having no correlation with the impressions that we have of the visible light transmission in this fluid. For example: the "Spirit vinegar", totally transparent for the visible light and absolutely opaque for the UVC
UVC Dose
For a given microorganism subjected to the action of the UVC, the effect of destruction depends on the intensity (I) of the radiation which it receives and time of exposition (t).
DOSE = I (mW/cm²) x t (s)  mJ/cm²    
The intensity "I" is given by the power of the lamp and its distance regarding the surface to be treated. The time is linked to the process pace or to the fluid flow inside the UVC generator.  
The DOSE is a constant variable corresponding to a kind of microorganism and it corresponds to the necessary UVC energy for decreasing his population of a 10 factor (90 %). 

The concept of logarithmic reduction corresponds
to the percentage of inactivation of the present germs. 
  • 90 % of decrease amounts to 1 Log  
  • 99 % of decrease amounts to 2 Log  
  • 99.9 % of decrease amounts to 3 Log
  • etc...  
To pass from 90 % to 99 % of reduction,
it will be necessary to double the dose
and to triple it to arrive at 99.9 % (for a determined germ).