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Thread: Dust collector bags not inflating?

  1. #1
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    Dust collector bags not inflating?

    I recently purchased a used delta 50-853 which is a two bag 3HP dust collector. I was able to test it at the guys shop but the ceilings were not high enough to allow it to run completely (just a quick pulse to hear it run). I understand that the bags are supposed to be hung by two hangers, but I figured that was just for convenience of not having ~5.5ft tall bags flopping down when the machine isn't on. To my surprise when I turned the machine on without the hangers and the bags kind of just flop around like the inflatable dudes out in front of a car dealership. Is something defective with this collector? Even when I put the bags on the hangers, they aren't taught like every other collector I've used are. They sort of inflate and take the general shape of the bag but still very loose.
    There are some small pinholes in the bags but I would expect that the power of a 3HP motor would still be able to inflate the bags. Any tips or suggestions are much appreciated!
    FYI this is my first post. Let me know how I did

  2. #2
    Welcome, Jack

    Three possibilities:
    1) The motor/impeller isn't moving enough air. This is hard to test, because it's hard to accurately measure absolute air flow. You could measure the current drawn by the motor and compare to the nameplate, though, and that would give you some indication if something is majorly wrong or not.

    2) The filter bag isn't presenting much restriction to the exhaust air, because the filtration isn't very good, holes in the bag, lack of "seasoning" on the bag, etc. Honestly, filter bags are terrible filters, to begin with, and if the have "pinholes" in them...

    3) Everything is fine.

  3. #3
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    A serious restriction of the inlet can cause this.

    Are you connecting it to the correct voltage? A 3 hp dust collector will not run very well on 120 vac.

    If the bags are very clean you may also have this problem. The bags will become more firm when the dust collector is running and has collected some saw dust.

    If that thing is running correctly, it should have enough suction at the inlet to suck your skivvies right off of you if you aren't careful.

    Charley

  4. #4
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    How is the suction? If your bags blow up like balloons you are causing excessive back pressure on the system. This is pretty common with the supplied filters and bags on a lot of DC's. This is why places like American Fabric Filter exist. Your filter bag should at the very least be soft to the touch like a sack of clothes, not hard like a balloon. Where problems sometimes arise are when the bag is too open. This lets it stay soft but, that is because it is not doing much of a job. You want decent filtering without a lot of flow restriction. Its a balancing act.
    Last edited by glenn bradley; 01-20-2019 at 9:41 PM.
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  5. #5
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    Did you inspect the impeller? May have ingested a chunk of something and put some notches in the blades. Also make sure the key is in the impeller and it's not slipping on the motor shaft.

  6. #6
    Your filters are fine!
    And here is why, years ago before MERV ratings they had % numbers such as 40% or 80%.
    The test conducted in a test chamber and 1 pound of dust was introduced into the air stream.
    After the filter was run for ten minutes the filter was removed and weighed to see what percentage of the dust was captured.
    Hence .5 lb increase in weight was a 50% filter.
    Now if you left the filter run in the chamber it would eventually would capture all the dust and the efficiency would increase till it was 100%.
    At 100% you are not moving much if any air and that is a technical term called plugged up.

    So if your filter doesn't inflate is no big deal as long as you have good suction.

    Now I have been in the HVAC industry for over 40 years. I have worked in clean rooms for the aerospace industry, pharmaceutical and so on.
    So I think I am somewhat experienced.

    I am now going to rant Bill Pence did bring dust collection to everybody's attention.
    He however did take data and presented it to create a demand for his product.


    Now I can bore you to death with technical data but forget the micron crap. For one thing the ONLY COMPANY THAT MAKES HEPA,SUPA ans UPUA filters is Flanders Filter.
    Two you will never get your wood shop cleaner than a operating room. It just isn't gonna happen.

    Three don't believe the manufactures data on dust collection systems they are not tested to NEBB standards. If your interested http://www.nebb.org/

    So put all the tech talk away and realize that dust collection is a glorified vacuum cleaner and nothing more.

  7. #7
    Quote Originally Posted by George Makra View Post

    So put all the tech talk away and realize that dust collection is a glorified vacuum cleaner and nothing more.
    Well, I, for one, only have HEPA-filtered vacuum cleaners, so...


    Respectfully, George, your opinion is definitely a minority view. Most people agree that fine dust has serious potential health risks, good filtration is essential, and bag filters are grossly insufficient (if not downright dangerous). I don't have the knowledge or background to defend the scientific merits, but lacking that, it seems wise to err on the side of caution.

  8. #8
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    Quote Originally Posted by George Makra View Post
    I am now going to rant Bill Pence did bring dust collection to everybody's attention.
    He however did take data and presented it to create a demand for his product.
    Now I can bore you to death with technical data but forget the micron crap. For one thing the ONLY COMPANY THAT MAKES HEPA,SUPA ans UPUA filters is Flanders Filter.
    Two you will never get your wood shop cleaner than a operating room. It just isn't gonna happen.

    Three don't believe the manufactures data on dust collection systems they are not tested to NEBB standards. If your interested http://www.nebb.org/

    So put all the tech talk away and realize that dust collection is a glorified vacuum cleaner and nothing more.
    George
    I understand where you're coming from. My background is in Instrumentation and Controls, including large industrial air handling equipment. And while I have/had issues with Bill's testing protocols, and had discussions, via the internet, with him about them, I will grant a tremendous amount of latitude simply because he is self taught and no-one else was stepping up to the plate. Yes, he has a product to sell, but his research and data is free to anyone that wants to wade through it.
    No one, not a single manufacturer, was doing anything to improve dust collection, in a non industrial environment, until he started to put his info on the 'net. Now there are multiple companies providing products for such a market. It's an improvement.
    No, a garage workshop will never be as clean as an operating room, but there is also not a million dollars in air handling equipment involved either, creating a negative environment.
    Everything is a compromise and each person has to do what they can afford and are comfortable with, and any time the air is filtered and recirc'd back into an enclosed space, compromise is taking place.

    Now, as for your final sentence, realize that many of the folks on this forum have a very, very, strong engineering background. They're data junkies. The math and concepts involved are well within their grasp. Share your insights, experience, and knowledge. Present the info and use the forum to teach and mentor.
    Dust collection is one of the "hot button" topics, and people are looking for real information. I know that I personally would be very interested in your viewpoints on the subject.
    Last edited by Mike Cutler; 01-21-2019 at 10:07 AM.
    "The first thing you need to know, will likely be the last thing you learn." (Unknown)

  9. #9
    Hi Jack. Welcome to the forum. Returning to your question, which is fine by the way. Does your dust collector have the original wiring or has someone put their own cords on it in the past? There is the possibility that someone could have wired it wrong and the fan turns backwards. It would still suck air but it will be anemic and that's why the bags don't inflate. I had an Asian version of that DC and the bags would be almost as hard as a bouncy castle kids play on. So disconnect it from power and open up the switch and motor covers and look at how it was wired.

  10. #10
    Join Date
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    Thanks for all the help guys! I will take the suggestion to switch the leads and see if that helps.
    It is a 220 machine that i am running on a 220 outlet so no issue there. Iíve been setting up my shop so i havenít gotten back around to the dc yet. Iím going to try to patch the small holes and give it a go and see what happens. I may be back for more!
    Side note: the bags seem generally thin and cotton like compared to the more firm synthetic feel of what Iím used to. Perhaps they are just old and worn out? Iíll look into new bags but thatís going to turn my 350 dollar score into a money pit.
    Jack
    Last edited by Jack Hovanec; 01-25-2019 at 9:05 AM.

  11. #11
    Jack those bags are only good for bigger dust and shavings so until you get better bags or cartridges, wear a good dust mask while you work in the shop even after you turn it off. The very fine dust will linger in the air for many hours.

  12. #12
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    What a stunning post....I could not disagree more.

    I will not forget " micron c***". The small micron stuff is the most dangerous to my health especially as I get older.

    The methodology of how to measure anything is dependent on what you are trying to accomplish. Measuring airflow for a clean room or operating room is completely different than for a dust collector in terms of the needed reliability of the measurements.

    The fan curves published by mfg in the past for dust collectors was not good. However, they have been improving and have been much improved. The curves provided in Wood Magazine seem to be pretty good. Not up to the NEBB standards but we are not measuring clean rooms.

    The best measurements for dust collectors in my opinion has been done by BobL on the Australian woodworking forum.

    The question becomes trying to match the accuracy needed and the methodology. Having reasonable methodology that is affordable and reasonable accuracy will help people improve dust collection.

    Bill Pentz....He has made a tremendous contribution to dust collection in home workshops. He has been transparent about why he did his work and his health problems. The use of cyclones in home dust collectors has been a great improvement allowing the filters to stay clean.

    Dust collectors for woodworking are not glorified vacuums. Dust collectors are high volume low pressure systems where vacuums are low volume higher pressure systems. Equating the two seems to be a misunderstanding of the equipment.

    I would agree with one thing that I will not get my shop cleaner than an operating room....but why would I even try.

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