Lamp variants

Arc lamp options

GEW offers lamp variants for its electrode arc systems.

Standard mercury (Hg) lamps emit broad-spectrum output across UV, visible, and infrared wavelengths. This output is shifted by adding small amounts of metal such as iron (Fe), gallium (Ga), lead (Pb), tin (Sn), bismuth (Bi), or indium(In) to the inside of the quartz tube. Mercury lamps with added metals are referred to as doped, additive, or metal halide.

Different types of tube construction materials, as well as coatings applied to the surface of the tube, are also used to either block or increase emission of certain wavelength bands.

Doping:

• Mercury (Hg) is the most commonly used GEW lamp.
• Iron (Fe) doped is the second most commonly used GEW lamp. Iron doped lamps shift part of the UV output to longer near-visible wavelengths which results in better penetration through thicker, densely pigmented inks. Often used as the final curing station on inkjet printing systems.
• Gallium (Ga) doped lamps are best for curing white inks and coatings containing titanium dioxide. This is because gallium lamps shift a significant portion of UV output toward wavelengths longer than 380nm. Titanium dioxide additives, which give white inks their colour, absorb almost all light below 380nm.

Lamp constructions:

• Ozone-free lamps contain surface coatings that block ozone generating wavelengths below 240nm. These are commonly used on laboratory units or water-cooled only UV systems to avoid the need for ozone filters or ducting on the installation. Any doped lamp variants can be produced with ozone-free quartz.
• HiC lamps boost total UV output by approximately 15% and increase UVC output by 30%. UVC wavelengths promote surface cure and are particularly important in some industrial applications such as hot melt adhesive curing. HiC lamps use a highly purified form of silica to manufacture the quartz glass tube/lamp which absorbs less UV light than usual and boosts output. Any doped lamp can be produced with HiC quartz.
• GEW also manufacture quartz windows from the same material with similar effects on UV output.