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Direct
UV-radiation contributes to the major part to UV-Curing,
a good reflector design will give another 30%
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Parabolic
type with parallel rays.
Elliptical
type bundles the radiation in the second focus.
Combination
of parabolic and elliptical type,
they stray or bundle the radiation in many
ways.
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The plant manufacturer
depending on the application selects the reflector type needed.
The reflector should be made of aluminum as this material has
best reflection characteristics in the UV-rang. It should be polished
and have protective coating made of anodized oxide. In some special
case, coated materials can also be used. This is a new technology
where selected materials, for instance glass coated with vaporized
metals that give a UV-reflection layers.
Such reflectors are able to reflect UV-radiation. Light and heat
will be transmitted or absorbed depending on the material chosen,
and can be removed with the cooling air. The glass reflector can
be used in cold mirror systems.
These materials are not
yet commonly used; however they might have a determining influence
in future technology.
The figure below shows a modern reflector
construction resulting in good lamp cooling.
To
avoid any unnecessary losses the aluminum extrusion is designed
in such a way that all rays are reflected that pass the lamp and
there are no multiple reflections
The holes in the extrusion are arranged
in such a way that they cannot be used as a rotation center in
order to close the extrusion during stand-by, thus also saving an additional shutter.
The exchange of the reflector sheets
is easy and cost saving. The initial status of the UV-system is
established each time the lamps and reflector
sheets are changed.
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