On a whim I ordered up an anonometer. Mostly due to the fact I wanted to see what the cfm was at the new drum sander. In the past I just figured it it what it is, but for 40 bucks it seemed good to know info. I have two 2hp dust collectors one at each end of my system. In tandem the greatest flow has always been in the middle of the run, getting the most out of both collectors. The outdoor collector has no bag, just a  dome of window screen and the indoor one has a Wix canister system. When I put the anonometer up to the 4” hose at the sander it says 5100 ft/min. Calculating the 4” diameter of the hose as 12sq inches ( 1 foot of area ) times the flow in ft/min gives me 5100 cfm which doesn’t seem possible. Is my math wrong or is this meter bogus ?

Paul

I think you need to convert the area of the hose to sqft before multiplying 

I was using Area= pi r squared. 

R is 2 ( 4” hose )  so 4 X Pi = roughly 12. Opps. Need to divide by 12. Thanks Lew ! 416 sounds more realistic 

Paul

Edited March 27, 20242 yr by Masonsailor

Square in to square ft need to divide by 12 swim/144= .083 sqft