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Thread: That ain't right

  1. #1
    Join Date
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    That ain't right

    Ok what am I doing wrong...got a Pyle PMA90 anemometer too check out my dust collection system. Set the area as per instruction to 1/2 the width of the hose (1.75 inch) x pie (3.14) it comes out to 5.495 used that as the area on my pyle, and holding the vane 1 inch from the hose, I get over 9000 cfm, so either I got the best HF 2 hp dust collector in history, or I am doing some thing wrong. Any ideas on what I need to do to get a good reading...
    Last edited by Mark E Smith; 05-19-2015 at 11:39 PM.

  2. #2
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    well if your trying for the area of a 3.5 Inch dia then the formula is Pix(R squared) so for a 3.5 " the radius is (1.75 x1.75)x3.14 = 9.61625
    "There’s a lot of work being done today that doesn’t have any soul in it. The technique may be the utmost perfection, yet it is lifeless. It doesn’t have a soul. I hope my furniture has a soul to it." - Sam Maloof
    The Pessimist complains about the wind; The Optimist expects it to change;The Realist adjusts the sails.~ William Arthur Ward

  3. #3
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    Thanks Don, forgot it needs to be squared, but looking it over just realized this formula on the Pyle is for FEET not inchs, so 1.75 is one foot 8 inch...duh...my hose openning ain't quite that big..lol..guess I got some sifering to do, plus it is actually a four inch PVC pipe, 3 1/2" was off the connector. Probably should use the actual pipe size, oh well something new to play with....

  4. #4
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    Mark,

    Are you not happy with 9000 CFM?

    Just don't let the kids get too close.

  5. #5
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    Quote Originally Posted by Leo Voisine View Post
    Mark,

    Are you not happy with 9000 CFM?

    Just don't let the kids get too close.
    I'd add a separator and get that down to around 7-8000 CFM just to be safe!
    A man is rich in proportion to the number of things he can afford to let alone. -Henry David Thoreau
    My Website


  6. #6
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    Oh one other thing I am reminded that my father always said was that Pi r square was wrong because pie r round...Cake R squared...
    "There’s a lot of work being done today that doesn’t have any soul in it. The technique may be the utmost perfection, yet it is lifeless. It doesn’t have a soul. I hope my furniture has a soul to it." - Sam Maloof
    The Pessimist complains about the wind; The Optimist expects it to change;The Realist adjusts the sails.~ William Arthur Ward

  7. #7
    Join Date
    Jan 2014
    Location
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    lol...yea once I got the right numbers in the area setting, came out a little more realistic...of course the Harbor Frieght listing of 1550 cfm is a little optimistic. The best I could come up with in 660 cfm with no hoses attached and the anometer flat against the the five inch port ("Y" removed) on the Dust Collector and the anometer set to five inch area (.136 squared x 3.14) most of my machines set to 4 inch where getting around 400 cfm some down to 320 cfm where it is split off to a 2 1/2 inch like the Router (2 1/2" to the top and 4" to the bottom) was getting 165 cfm top and 305 cfm bottom. Not great, but seems to work Ok. My CSMS is also split, but closer to the DC, so I get 190 cfm top (reduced to 2 1/2 connector) and 4" bottom port getting 390 cfm. So overall not great numbers, but it is a HF DC and I am using 4" PVC ductwork, so I guess that is the best I can hope for....for anyone interested the area setting for the pyle are .087 for four inch and .034 for 2 1/2" that is what I used...glad I am not getting 9000 cfm, probably be sucking up my watch into the DC, hate taking that bag off to retrive stuff....lol

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