I doubt whether there would be an advantage provided you can guarantee
your compressed air is totally contaminant-free, which is a very tall
order. Do not rely on ordinary filtering, coz it's no use, no use at
all. What is in ordinary industrial compressed air?
- oil vapours from the compressor lubricant
- thermally decomposed hydrocarbons resulting from ht above oil being
subjected to high temperatures in the compressor cylinder (the air can
momentarily rise to hundreds of °C)
- carbon dioxide from the same source
- moisture, by the litre, even where the RH is low
- reactive carbonic and other acids
- dust particles, smaller than the input filter
- rust particles from galvanised iron piping (reaction from the acids
eats through the zinc in no time flat)
- zinc carbonate (ditto)
- etc.
Not a nasty soup to put on your precious boards. The easiest part to
deal with is the moisture (cryogenic filter plus silica gel, provided
the silica gel is maintained properly). For the particulate, it is
possible to go down to 0.1 µm filters, via a series of coarser filters.
For the acid gases, a lime filter (also to be maintained) between the
cryogenic and the silica gel will prolong the life of the latter. That
leaves the organics. A series of carefully selected active carbon
filters (also to be maintained) capable of adsorbing the oil (large
molecule) and decomposed HCs (smaller molecules), before the mechanical
filters. That should do the trick, provided you use no metallic pipework
after that lot. Quite an expensive proposition in both capital and,
above all, maintenance costs.
The alternative: bottled air produced as the distillate of liquid air.
It is cheaper than nitrogen and just as good. The only advantage of
nitrogen is that it would avoid oxidation, but this is not an issue, as
you bake the products in an oven afterwards, anyway. If the quantities
required justify it, you may care to consider a liquid air tank.
Brian
Fallows David wrote:
> I want to implement a simple process by which we'd blow the rinse water
> off of our boards coming out of wash prior to putting them into an oven
> to dry. I plan on purchasing an Ionizing gun, but is there any
> advantage in blowing nitrogen vs filtered compressed air?
>
>
>
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