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Thread: Dust collector replace bottom bag with filter bag?

  1. #16
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    Quote Originally Posted by David L Morse View Post
    Do yoou have an ammeter? If so you can get some very informative relative flow measurements.
    Hopefully you are referring to an anemometer for measuring air flow, and not an ammeter which is used for measuring electrical current. The anemometer approach has already been mentioned several times in this thread. I suppose it helps to read the entire thread.
    David

  2. #17
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    Quote Originally Posted by David Buchhauser View Post
    Hopefully you are referring to an anemometer for measuring air flow, and not an ammeter which is used for measuring electrical current. The anemometer approach has already been mentioned several times in this thread. I suppose it helps to read the entire thread.
    David
    No, an anemometer has well known issues measuring airflow in dust collection systems. I'll not repeat those here, hopefully you've read all of the threads discussing this.

    I am most definitely referring to an ammeter. Motor current (and even better if you can measure it is input actual power, not apparent power) is a very good indicator of airflow (actually mass flow or SCFM rather than ACFM).
    Beranek's Law:

    It has been remarked that if one selects his own components, builds his own enclosure, and is convinced he has made a wise choice of design, then his own loudspeaker sounds better to him than does anyone else's loudspeaker. In this case, the frequency response of the loudspeaker seems to play only a minor part in forming a person's opinion.
    L.L. Beranek, Acoustics (McGraw-Hill, New York, 1954), p.208.

  3. Easy experiment. Take the bag off and you will see what no restriction will be. If it is better, than more filter area will help.

    I have made a changes recently that are dramatic enough that no measurement was needed, I could see, feel and hear the added air flow.

    I suppose for a very low tech way of measuring how well the air is moving you can rig something up to keep a dust port at a constant height from a table and pick some objects to get sucked up. You go with a variety of weights - ie several small offcuts increasing in size or using a measurement of sawdust to see how much is collected. Run a before and after test and see if no filter picks up heavier object or more sawdust.

  4. #19
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    Keep in mind that a cyclone puts a terrific hit on your airflow even for blowers that are designed as part of a cyclone. When you add a cyclone ahead of a blower that is not designed for it, the hit can be even more substantial. This should be expected. You are adding something to the path, yes? Having the benefit outweigh the impact is where the balancing act comes in.
    "A hen is only an egg's way of making another egg".


    – Samuel Butler

  5. #20
    Tried removing the bottom bag on the dust collector and noticed there was a little improvement, but nothing great. I then rearranged my piping to get the jointer planer close to the dust vac with only one turn - this did the trick. Other machines are also working fine.

    Thanks to all that responded.

    Regards,
    Frank

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