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Thread: Why Are Chips Bypassing My Cyclone?

  1. #1
    Join Date
    Oct 2013
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    Berwick, Nova Scotia, Canada
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    Why Are Chips Bypassing My Cyclone?

    Machine is King Canada 3HP Cyclone (same as Laguna 3HP manual cleaning) I moved from a 2HP with canister running through a Super Dust Deputy on a 55 gallon drum (huge footprint)

    I am running through a combination of duct and flex, and I already know it is not the optimum set up. It goes like this

    6 - 6" reducer. 6" T. Two lines.

    Line 1 - 10' of flex to a 6-4" reducer. 4" wye. One branch to 4" port on jointer, the other to the 4" port on my table saw. Both branches have 4" blast gates.

    Line 2 - 2' of flex to 6" elbow. 6' of 6" duct to another elbow. 4' of 6" duct. 10' of 6" flex to a 6-4" reducer. 4" blast gate. This branch services my 20" planer and my drum sander.

    I know that this machine is not as efficient as the SDD, however, I did not expect the amount of chips bypassing the drum as I am seeing. It is not too bad as long as I only have one blast gate open. If I have two open, even the two on the one line, the little bag on the filter fills quickly with chips. I tightened the clamps holding the drum lid on, and I do not feel any sign of leakage there.

    I plan to replace the T with a Wye, and use two elbows at each corner, each at 45 instead of one at 90.

    Thoughts as to what may be happening to cause this issue?

  2. #2
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    The most common cause of chips bypassing the bin/barrel and going on to the filter is an air leak at the barrel or in the connections between the "funnel/cyclone" and the barrel.

    The way the cyclone works is the air and dust are drawn into the cyclone chamber and downwards. At one point the air changes direction to go upwards into the center pipe in the cyclone portion. When it changes direction the air loses velocity momentarily and thus loses its carrying capability. Gravity then takes over and the saw dust drops into the barrel/bin. If you have an air leak in the barrel/bin or any of the connections between the barrel and the cyclone, the small air leak is enough to push the saw dust into the center pipe and on to the filter.

    Check very carefully for air leaks in the barrel/bin and the connections between the barrel/bin to the bottom of the cyclone. Small leaks at that point can cause the problem.
    Last edited by Ken Fitzgerald; 03-28-2015 at 5:18 PM.
    Ken

    So much to learn, so little time.....

  3. #3
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    Quote Originally Posted by Ken Fitzgerald View Post
    The most common cause of chips bypassing the bin/barrel and going on to the filter is an air leak at the barrel or in the connections between the "funnel/cyclone" and the barrel.

    They way the cyclone works is the air and dust are drawn into the cyclone chamber and downwards. At one point the air changes direction to go upwards into the center pipe in the cyclone portion. When it changes direction the air loses velocity momentarily and thus loses its carrying capability. Gravity then takes over and the saw dust drops into the barrel/bin. If you have an air leak in the barrel/bin or any of the connections between the barrel and the cyclone, the small air leak is enough to push the saw dust into the center pipe and on to the filter.

    Check very carefully for air leaks in the barrel/bin and the connections between the barrel/bin to the bottom of the cyclone. Small leaks at that point can cause the problem.
    Will do. Thanks.

  4. #4
    Quote Originally Posted by Ken Fitzgerald View Post
    Check very carefully for air leaks in the barrel/bin and the connections between the barrel/bin to the bottom of the cyclone. Small leaks at that point can cause the problem.
    You can try wrapping the entire drum in a plastic bag, if you can find one large enough. Seal the top around the hose from the cyclone as best you can. Now turn the unit on and if the bag sucks to the drum, or if the point near the bag/hose point sucks smoke from a smoke stick in, you've got a leak.

  5. #5
    I put a layer of foam weatherstrip on the top edge of my drum, then use spring clamps to hold the lid down. I had the same problem, till I got my leaks fixed. One was betwen the motor plate and the top of the cyclone. Different brand of cyclone.

  6. #6
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    I spent sometime redoing the seals on the flex hose between the drum and the cyclone. I even used some caulking putty on one of the joints. I am fairly confident that I have taken care of any potential leaks there. More closed cell foam weather stripping between the barrel and the lid is my next step. I have also ordered the wye to get the T junction out of the equation. I figure that one that close to the cyclone maybe disturbing the air stream. I plan to leave no stone unturned until I am convinced that it is working the best it can.

  7. #7
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    Is it larger chips or fines (flour) that is bypassing?
    Mike

  8. #8
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    Both. Not real concerned about the fines, the filter takes care of them. It is the chips, as they were filling the filter bag very quickly, less than half the barrel was full and I had to empty the filter bag.

  9. #9
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    Sometimes larger particles can be carried over from an uneven surface on the inside. Could be a rough weld, ledge, etc.

  10. #10
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    Quote Originally Posted by Michael W. Clark View Post
    Sometimes larger particles can be carried over from an uneven surface on the inside. Could be a rough weld, ledge, etc.
    So where do you suggest I look for something like that?

  11. #11
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    You'll need to look on the inside after you correct the inlet arrangement. Keep in mind, it may be the cyclone efficiency too since you are passing both fines and large particles.

  12. #12
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    Sometimes larger particles can be carried over from an uneven surface on the inside. Could be a rough weld, ledge, etc.
    My cyclone has a vacuum hose inlet that is connected to the collection barrel by a hose wouldn't this cause the same issue ?

  13. #13
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    Quote Originally Posted by mike mcilroy View Post
    My cyclone has a vacuum hose inlet that is connected to the collection barrel by a hose wouldn't this cause the same issue ?


    I wish mine used that system. I thought it did when I ordered it.

    No it would not. The suggested causes would result in air getting into the barrel, your line is sucking air out to retain the bag.

  14. #14
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    Quote Originally Posted by Mike Chalmers View Post
    So where do you suggest I look for something like that?
    Mike, Sorry for the short response above. As you know a cyclone operates on an efficiency curve, it captures a higher percentage of larger particles and a lower percentage of smaller particles. We have had cyclones that caught the fines but allowed larger chips to bypass. The first thing you check is that the cyclone is sealed at the dust discharge.

    After that, if the problem still persists, you look at the inlet arrangement to see if the ducting could be an issue (causing turbulence as the air enters the cyclone). Sometimes, this is not easily improved. The main thing is that you do not have elbows causing the air to turn counter-current to the cyclone (as viewed from above). Ideally, you want about 6 straight duct diameters at the cyclone inlet.

    If the problem still persists, the next thing to check is the interior of the cyclone. If the curved surfaces are not smooth (large weld gaps, not enough breaks on the curved parts, mis-alignment between body and cone creating a ledge, build up, dents from users trying to free plugs, etc), the large particles will hit these places as they spin around and get thrown back into clean gas vortex and go out the top.

    Since you have changed cyclones and getting both fines and chips over to the filters, I suspect it may be related to the cyclone efficiency itself. If this is the shorter Laguna model compared to the Oneida unit, the Oneida unit may be more efficient. Cyclone efficiency is not just about pressure drop, but about proportions and size as well (the last two has a much larger effect on fines).

    Hope this helps,
    Mike
    Last edited by Michael W. Clark; 04-01-2015 at 10:26 AM.

  15. #15
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    Just curious. How can an 1 1/4" pipe extending into the cyclone not cause the same disruption as a bumpy weld or ledge, I know why the hose inlet is there for the collection bag but still this inlet is much larger than the worst weld.

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