Results 1 to 9 of 9

Thread: DC in a very low overhead shop

  1. #1

    DC in a very low overhead shop

    I have very little headroom to place a cyclone. Others have responded to the issue of motor placement and I am grateful for the schooling. But I am unsure about how to manage the limited space relative to a waste bag or bucket under the cyclone.

    Does this have to be air tight and not loose pressure to the system? It seems like leaks here would loose vacuum to the cyclone.

    What is the smallest practical size I should consider? (Yes, it depends. But lets say a day of making cabinets, maybe some chairs and not the commercial thickness planing of 4k board feet of Red Wood.)

    Could I pancake this box, loosing vertical and gaining horizontal dimensions?

    Would the dust spread out in a low wide box or would it just clump up at the bottom of the box.

    I may end up with a small box that has a hose to a large shop vac and I just empty it as needed. How have others managed the low ceiling of a basement workshop?

  2. #2
    Quote Originally Posted by Bruce Seidner View Post
    Does this have to be air tight and not loose pressure to the system? It seems like leaks here would loose vacuum to the cyclone.
    If you follow Alan's advice to go push-through, then you can use a garbage bag for your debris. You could probably get quite close to the floor and still fill the bag efficiently. And easy to empty, too. Just remove the bag, put a new one on, and resume. You gotta love that.

    People are also pretty happy with their Thien separators (shameless plug). Depending on the amount of use (coupled with whether you're filtering or exhausting outside), this may work for you as well. It would certainly meet your height requirements.

  3. #3

    I thought I was just dyslexic

    You know I was looking at Alan's pictures and knew there was something I did not understand. You could adopt a wrestling name and call yourself "The Separator." Thank you for separating this and clarifying that I have no idea what a push through means. In a "whats wrong with this picture" I could not fathom why the blower was pulling air through what I identified as the INLET of the cyclone and why machines where connected to the top where the blower was supposed to be as I understand the mechanics.

    Whats going on here?

  4. #4

    I am wrong again...

    Google speaks, "The most common cyclone dust collector configuration has the fan on the clean air side (pull through). Push through models with the fan on the input side are available."

    Ok, the blower is sucking from the machines directly in a push through and the dust goes round and separates with cleaner air going out the top of the cyclone to the external filter and falling down with some oomph into the lower bag.

    I don't understand why this would be preferable.

    I think I see that if it looses air at the bottom it matters less because that is just waste air laden with particles, though it could get messy and undermine the project of removing particle from the air. But it would allow me to duct the bottom to a more convenient place over my retaining wall and into the shop instead of having to crouch around in my crawl space to keep emptying my box.

    Why do people choose push through designs who are not limited to crawl spaces and Hobbit like habitats?

  5. #5

    So I sez to myself....

    Because I have no access to Alan's grandfather's pick axe and wheel barrel to increase the depth in my crawl space I have come up with a new plan. This plan may have no real world correlates because I am unencumbered with actual engineering understanding or data and all of this is new to me. That said, I have enough room in my crawl space to mount the cyclone and have it in push mode. The cyclone is 41" overall length, 18" in diameter, 6" inlet, 7" outlet on top and 6" discharge on bottom. It will have a 7" short run out the top to Moby, my 12' long fabric filter. The New York Blower Size 136 Compact GI Fan will mount to the side in a push mode, essentially coupled to the cyclone at the side inlet.

    Here is where it gets interesting.

    Because I lack the height to have much of a waste container, and it is a pain to get around my bench crouching and watching I don't bump my head, I will have a short run of pipe under the work bench for discharge from the cyclone. The work bench extends out into the crawl space and is mounted about a foot above the retaining wall at the end of the shop. The cyclone will discharge into a plywood "tall kitchen garbage" container I will build and line with tall kitchen plastic bags. It seems that in push mode there will be more than enough air through a 6" pipe for the discharge to stay clear. I will use transparent 6" hose rather than rigid pipe to keep this flexible and visible. It might need a whack of a broom handle now and again. It would also be easily cleaned with a shop vac.

    Because the impeller is aluminum and because unintended objects, anything from tape measures to screws are routinely sucked into these 6" systems, I will make a tall plywood <drum roll> Thien separator to catch the big bad stuff and to have a more convenient place to empty material in the shop. It will also be a convinient hub to run my pipe to the machines also integrated into the benches that are being built now. I can integrate a unit like this while I am rebuilding the shop without too much trouble. The whole cyclone/blower thing was ungainly and difficult to place given my limited ceiling height and space.

    The Thein separator unit and material discharge box from the cyclone can be tucked under a bench or I can build the bench around them and still have strong flat plywood vertical surfaces for mounting shelving, etc.

    Now, this is where someone, other than myself, says I have it backwards or something to that effect.

  6. #6
    Join Date
    Jan 2004
    Location
    Fredericksburg, TX
    Posts
    2,576
    Bruce,

    Can you go up into the overhead with the motor section of the cyclone? It might be possible to have the motor extend into the attic/ceiling joist space and hand the cyclone on the ceiling joists at the top flange. You would only need to build a box to go over the motor in the attic and have it still within the lower shop space. Not a standard installation, but sometimes you need to think out of the box. You can also cut the height of your dust bin and put up with needing to empty it more often.

  7. #7

    complications

    I can complicate opening a jar of mayonnaise but here I am stuck with nowhere to go. I would like to think outside the box, but the box is buried at present. This is a 60 year old brick rancher on a hill with a garage under the the living space. I have to laugh thinking about the DC system I have outlined. But as of today it is what makes sense, albeit with a somewhat Rococco sensibility. Ain't no Shaker that would entertain this Rube Goldberg DC plan.

  8. #8
    Join Date
    Feb 2003
    Location
    Washington, NC
    Posts
    2,387
    Bruce, sorry I assumed my photo and prior reading would have explained a "push-through" cyclone so I didn't include a description. Don't feel bad, I knew a professional woodworker who couldn't get his head around the concept. He was willing to bet a "push-through" just can't work. The cyclone doesn't care where the blower is located, just as long as the air goes through it the correct way.

    As you noted in your post, a "push-through" is minimally affected by minor leaks in the dust collection bag (leaks just make a mess). Conversely, in a traditional "pull-through" cyclone, the hose connection at the bottom of the cone, the hose connection on top of the dust bin lid, and the seal between the lid and the bin MUST BE PERFECTLY AIR TIGHT. If they are not, separation will be significantly degraded and dust will pass through the cyclone to the filter(s).

    Another benefit of a "push-through" cyclone is that dust can go right into a trash bag with no messy dumping a bin into a trash receptacle. This is the main reason I chose a "push-through."

    Another issue that may cause you a bit of a problem regardless of configuration- in ALL cyclones- dust exits at the bottom of the cone mainly due to gravity, so a dust bin or bag must be directly below the cyclone. You can fit a bag in a very small space below the cone- the bag will just pancake out as it fills with dust. It WILL NOT WORK to run the discharge horizontally to another location (without a helper blower like Oneida uses with their floor sander rig).

    If you have a lightweight aluminum or otherwise fragile impeller, you might want to consider adding small sump box with the inlet on one side offset below the outlet on the other to catch "tape measures" and other big items from entering the blower. Let me know if you need a drawing of it. I have indeed sucked up a tape measure, a chuck key, and misc nuts and bolts with no damage to my steel impeller. Though I believe your blower is big enough to overcome the static pressure resistance of both, one of Phil's baffles and a cyclone, you really don't need a full baffle separator and will have better CFM without it. Remember, every, inch of duct, inch of flex (especially flex), fitting (especially 90's), filter, cyclone, or other separator will have a negative impact on CFM and collection at the source.
    Last edited by Alan Schaffter; 05-05-2010 at 11:25 PM.

  9. #9

    re-do

    I am going to have to re-evaluate the mounting of the cyclone and likely buy a pick axe to do some excavation for the bag. I would appreciate a drawing and/or reference to a sump box. It sounds like the separator is over-kill that impacts the system significantly. Given the fact that this impeller is aluminum I want to be sure it is protected. I may have to do some serious excavation if I have to configure this as a pull-through. But if digging out some dirt is the worst of it I can't see much to complain about.

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •