Dust Sniper (quiet extractor system)

Step 9 The Outer part 2 - Air Exit and filtration

After all that effort, we don't want to just blast out the air into the atmosphere. It is a happy coincidence that a filter, as well as removing very small particles that can kill us, is also a useful sound deadening material for the exhaust passage. This time fortune really did smile upon us, and a perfectly sized, HEPA filter fell from the gods (well, from our friend who works for a big pharmaceutical multinational who thinks nothing of skipping anything that is not made of purest, unmarred angel essence) into our gratefully receiving lap. This is not strictly necessary, as the vacuums have filters (though they are fairly pathetic in comparison) but certainly a welcome boon.

HEPA stands for 'High Efficiency Particulate Absorbing (or Arrestance, or even Air filter, depending on who your talking to)'.  Basically is is pretty much the best commercially available air filtration of the sort that relies on the air passing through a fine mesh which catches the dust particles.  

"The HEPA standard exceeds the MERV specifications because they are the only mechanical air filter with an efficiency of 99.97% at 0.3 microns. This makes them at least 50% more effective than other types of mechanical air filters." http://www.hepafilter-pro.com/Filter_Ratings.php  (For the grades of filter : http://www.filtration-engineering.co.uk/air_filter_testing.htm). 

So we have one of these babies to integrate into the DS. As this will be right by the air outlet, it needs to be heavily soundproofed to make our other efforts worthwhile. Now is the time to deploy the lead!