DRATHORE – BLOG

What is UV?

                 c = f * l

c = speed of light, f = frequency, l = wavelength

light:      electromagnetic radiation

rule:   The shorter the wavelength, the more active the radiation.   

Ranges  of UV Light :

Effects of UV radiation

• Chemical effects
  • Curing of plastics, colours and laquers, glues
  • Photochemical effects
  • Cracking of harmful substances in waste water
  • Cracking of bad odours in air
• Biological effects
  • Burn, sunburn
  • Human skin ageing
  • Medical therapy
  • Disinfection of water, air and surfaces

UV-lamps, relevant factors

• quartz tube diameter, electrodes, seals, sockets and connection leads
• spectra, doping, quartz types
• energy proportion
  30% UV, 15% light, 55% heat (IR)
• life time

Characteristics of UV-lamps

• Lamp power in W/cm
• Spectrum, doping (Filling) and quartz type
• Lamp tube diameter
• Lamp operating voltage (V)
  lamp operating current (A) or power
• Arc length
• Total length (inclucing sockets)
• Sockets (dimensions, ceramic or metal)
• Lead length

Life time of UV-lamps

 What influences lamp life duration ?

1. Cooling
   Air exhaust temperature, amount of air exhaust,
   air distribution over the lamp
2. Lamp selection
   matching to the application
   (spectrum, tube diameter, electrical values)
3. Lamp quality
   Halogen cycle preventing blackening, “Ever Clear”
4. Treatment by customer
   careful handling and installation, regular cleaning

Electrical operation of UV-lamps

1. A ballast is necessary for limiting lamp the current and responsible for the lamp power.
2. Types of ballasts/power supplies:
3. capacitive (constant wattage power supply)
4. inductive
   1. chokes                                 (up to ~5 kW)
   2. Step up transformer with choke (up to ~9 kW)
   3. Leakage transformer (over 9 kW)
5. inductive with saturable core (transductor)
6. inductive with SCR control (Triac)
7. fully electronic EPS (up to 17 kW)

Devesh K S Rathore

DR Optical Disc India Pvt. Ltd.

drathore@dr-odi.com