Dust Collector airflow dynamics question

You should not reduce at collector only at tool . You should have 4inch pipe at the tool and reduce to fit the too

I’ll give that a try. Thanks woodman71

-- Steve in AZ

4” dia is 12.5 sq in while 2-1/2” dia is just under 4 sq in or about 1/3 the raw area and over time, volume. Couple that with the higher resistance of the smaller hose and a significant loss of suction is to be expected. Remember too that the smaller diameter makes the system more prone to clogging.

M

-- The hump with the stump and the pump!

Also consider that air resistance increases with the cube of the air speed. So if air needs to move three times as fast to make up the same volume (e.g. CFM), it needs 27 times the force (suction) to move it (not likely gonna happen…), so you won’t get as much CFM through the smaller hose, especially if is it a significant portion of the total hose length.

There is also a minimum air speed at which particles will stay suspended (depending on particle size and mass). So increasing duct diameter, past the point where the air speed drops below the carrying speed, is not a solution either.

Generally, unless runs are very long, it does not pay to increase duct size past the size of the inlet to the extractor.

As stated before, if you have to reduce the duct size to fit the tool (dust producer) then do so as near to the tool as possible.

Andy

-- Andy - Arlington TX