R & D
A very important part of making a UV system work, is the quartz
parts. Important because all UV energy has to pass through this,
with a loss - Quality determines how big the loss will be. First it
has to pass the lamp it selves and then the "window" that
closes the housing. The right choice of quality is the key to
success. As the price goes down very fast on decreasing quality, it
is easy to make a poor choice.
The lamp of course has to be made of the best quality. All of the
UV energy comes from this source and a loss at this stage would make
good work on the rest of the system without any value. Lamp quartz
comes under different trade names (Suprasilâ, Ilmasilâ, GE124),
but can all withstand the temperature needed for the plasma to
radiate UV down below 200 NM. Further none of these will block out
UV-C as long as you keep the surface temperature under 1000-1050 degree C.
Very cheap lamp types, make of poor quartz quality, has quite a high loss
of UV; and
you will not be able to determine why your system performs badly.
The window, which all the energy has to pass, should also be of
very high quality. Suppliers of the same material as mentioned above,
can supply plates or cut-tubes in the right dimension and the right
quality. Surely it seems obvious not to choose a better quality for
the window than you made on the lamp-type. But if your lamp-quartz
cuts of 60% at 220 Nm and the window does the same, the result is
almost no UV in the low range (60% of 60% = 36%).
||Here is shown the difference between two types
of quarts - loss in the UV-C area. Red- GE214P and pink GE124.
Almost the same difference is seen between Ilmasil PS and
It can be seen that there is quite a big loss using GE124.
Using this as both lamp and window material would make you
loose app. 50% of the UV-C
Another use of quartz in a UV system is as reflector material,
coated with a layer that reflects UV light (Cold mirror). As
this material is not supposed to transmit UV light, but only needs
to withstand the high temperature there are several options for flat
or circular types of material. Some common trade names is
"Duran", "Robax" or "Borofloat" and
are glass with a max. working temperature from 400-700 degree C -
depending on the type.
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