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  1. #61
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    Quote Originally Posted by jack620 View Post
    Hi Jon,
    I think as a start you could simply find a 4" design you like and scale it up to 6". I would just scale it up by 50%. Although the cross-sectional area of the ducting increases with the square of the diameter, so does the area of the slot and the collector bin. They look fairly simple to make, so be prepared to experiment. Don't be blinded by science!
    Hi jack620,
    OK, I ratted around all the building a Thein Baffle videos I could find and the clearest was one by Hornberger, even that didn't give away too much in dimensions, but from what I could gather the ID for a 4" inlet was about 750mm. Going on your rule of thumb, this would put a 6" one at around 1100mm, which is a bloody monster! Not too many garbage cans would be that large. I think for the scale think of my operation, that would be a more than a tad over the top. Ant and sledge hammer analogy. SO I could scale back to a FM-300 and a 4" SDD or Thein, which is more the scale I'm looking at. Incidentally, he used a 4" round to oblong adapter, would that make some difference?

    I watched this comparo, Thien Baffle vs. Cyclone: Efficiency Comparison — YouCanMakeThisToo. From what I can gather he's using a Harbour Freight equivalent of an FM-300, but he's using a 5" SDD! That would tend to skew the figures, I think. The test shows the cyclone beating the Thein for efficiency. Your thoughts?

    Incidentally, using either a Thein or an SDD with the FM-300, I could up the efficiency by separating the blower from the separator (with the filter and bag on), mounting the blower with the inlet vertical down directly into the outlet of the Thein or SDD and connecting up the bag unit with a piece of straight pipe, which would get rid of the energy sapping corrugated bend.

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  3. #62
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    Quote Originally Posted by jon542 View Post
    Hi Dave,
    I'm adding it to the FM-400, or that's the intention. The reason being that I want to separate out the chips, shavings and most of the dust before the DC to save me having to be emptying those blasted plastic bags with monotonous regularity when I'm working. As has been pointed out, I'm no spring chicken and the body isn't as flexible as it was. What flexibility was left took a hit with the L3-L4-L5 fusion. If I can get the frequency of emptying down to once or twice a year, that'll suit me fine. Remounting the damned things is the killer. If I wasn't on a minuscule budget I'd look seriously at building a mini electrostatic precipitator and have that empty into a bucket like the Thien, or cyclone.

    I already have an idea or two about modifying the bags to make them easier to remount by fixing an elastic band to the top of the bag to hold it in position while I wrestle the clamp back into position. Reducing the overall length of the bags won't matter, seeing that the amount they collect should be small.
    Thanks, that helps a lot. Since you need to keep the existing separators and desire to just reduce the the frequency of bag handling I would look for the lower pressure drop rather than higher separation efficiency.

    Both of those parameters vary with the size of the separator, pressure loss decreasing with the fourth power of scale factor. Efficiency will also decrease with increases in size but much more slowly than pressure, roughly the 3/2 power of scale. So pick a large trash can and build to match that.

    Build the top hat configuration, not the one with the elbow.

    Here's a thread on Phil Thein's forum discussing geometry trade offs. Pay particular attention to the information on inside height. Pressure loss increases rapidly with reductions in height. Ignore the first post on that thread.

    Here's another thread on that same forum. It documents a nice build and includes dimensions as well as test data. Post #99 is especially informative. Increasing the height by maybe a third will help a lot with pressure loss. You need to increase that inlet anyway since you have larger duct. I assume your\'re going to run duct between the separator outlet and fan inlet so forget the air straightener. If there's a chance that you will mount the fan directly above the separator some time in the future then build to match rotation.

    Oh, one more thing. A few strong magnets make for more pleasant bag replacement. That clamp is much easier to handle with two hands.
    Dave

  4. #63
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    Quote Originally Posted by jon542 View Post
    Going on your rule of thumb, this would put a 6" one at around 1100mm, which is a bloody monster! SO I could scale back to a FM-300 and a 4" SDD or Thein, which is more the scale I'm looking at. Incidentally, he used a 4" round to oblong adapter, would that make some difference?
    If you're going to buy a new DE I wouldn't get a 2HP. Definitely get the 3HP. Given your proposed duct run you want as much grunt as you can afford. Yes, 1100 is impractically large. But maybe there are smaller designs that you can scale up? Perhaps the reason his was 750mm was more to do with chip holding capacity than reasons of efficiency? I don't know much about Thein's sorry.

    Quote Originally Posted by jon542 View Post
    The test shows the cyclone beating the Thein for efficiency. Your thoughts?
    I'm not surprised. The SDD would have been designed and tested in a commercial facility. Possibly flow modelled on a computer. Most (all?) Theins are put together in a shed.

    Quote Originally Posted by jon542 View Post
    Incidentally, using either a Thein or an SDD with the FM-300, I could up the efficiency by separating the blower from the separator (with the filter and bag on), mounting the blower with the inlet vertical down directly into the outlet of the Thein or SDD and connecting up the bag unit with a piece of straight pipe, which would get rid of the energy sapping corrugated bend.
    This is what I did with my 2HP DE and SDD. You could do the same when funds allow. I managed to find these filters on special for $77 each. When new they have almost immeasurable pressure loss. Time will tell how they go when coated with fine dust.
    Attached Images Attached Images

  5. #64
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    Quote Originally Posted by jack620 View Post
    If you're going to buy a new DE I wouldn't get a 2HP. Definitely get the 3HP. Given your proposed duct run you want as much grunt as you can afford. Yes, 1100 is impractically large. But maybe there are smaller designs that you can scale up? Perhaps the reason his was 750mm was more to do with chip holding capacity than reasons of efficiency? I don't know much about Thein's sorry.



    I'm not surprised. The SDD would have been designed and tested in a commercial facility. Possibly flow modelled on a computer. Most (all?) Theins are put together in a shed.

    Thein baffle vs Dust Deputy-finisheddusty-jpg

    This is what I did with my 2HP DE and SDD. You could do the same when funds allow. I managed to find these filters on special for $77 each. When new they have almost immeasurable pressure loss. Time will tell how they go when coated with fine dust.
    Well done! Looks like you are squeezing maximum performance out of that 12" fan in a cyclone/filter configuration.
    Dave

  6. #65
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    Quote Originally Posted by dmorse View Post
    Well done! Looks like you are squeezing maximum performance out of that 12" fan in a cyclone/filter configuration.
    It's certainly a lot better than it was!

  7. #66
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    [QUOTE=jack620;2175136]If you're going to buy a new DE I wouldn't get a 2HP. Definitely get the 3HP. Given your proposed duct run you want as much grunt as you can afford. Yes, 1100 is impractically large. But maybe there are smaller designs that you can scale up? Perhaps the reason his was 750mm was more to do with chip holding capacity than reasons of efficiency? I don't know much about Thein's sorry.

    Hi jack620,

    NOW we're cooking with gas! That is pretty much what I was thinking of. How good was that setup? I assume that's a home made blower powered by a 2 HP motor. I assume your ducting is 5" flex, and it's a 5" SDD?

    My thought was getting an FM-300, disassemble the blower from the collector, mount the fan as in your setup, and instead of the flex bend connect separator to the the blower, use a piece of straight pipe. That takes the bend and the corrugated internal surface of the flex out of the equation. The question then is whether I build a Thien, or use a SDD ....

    I see the elephant in the room, the availability of 5" pipe and fittings. That puts us back in the realm of 6" pipe and an FM-400. I'd envisage the same sort of setup. I gather the twin bags and filters are required to handle the air flow. I'd disassemble the blower from the separators, mount with the axis vertical and short couple to the Thein/SDD, then make an elbow very much as you have in your rig to connect to the (secondary) separators.

    Here's a question, how much efficiency would be lost by retaining the separator(s) that come with the FM's?

    Hornberger's Thein ID WAS predicated by the size of his chip bucket. That was a nice piece of woodwork too. He was using around a 2HP, or smaller, home-built blower, and he was using 4"ducting. His setup was for a single machine.

  8. #67
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    Quote Originally Posted by jon542 View Post
    Here's a question, how much efficiency would be lost by retaining the separator(s) that come with the FM's?
    I'm not sure what efficiency you're referring to but there will be a loss of static pressure. That pressure loss results in a lower flow rate. Assuming the FM 300 has a 300mm fan and a 490mm or so separator the difference at 600 CFM or so will be around 17%. I don't know the fan size or separator diameter of the FM 400 but the loss at 600CFM would certainly be less. Note that the loss increases approximately with the square of CFM.
    Dave

  9. #68
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    Quote Originally Posted by jon542 View Post
    I assume that's a home made blower powered by a 2 HP motor. I assume your ducting is 5" flex, and it's a 5" SDD?
    All correct. Here's a recent thread on how I built the DE. 2hp DE Build

  10. #69
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    Quote Originally Posted by dmorse View Post
    I'm not sure what efficiency you're referring to but there will be a loss of static pressure. That pressure loss results in a lower flow rate. Assuming the FM 300 has a 300mm fan and a 490mm or so separator the difference at 600 CFM or so will be around 17%. I don't know the fan size or separator diameter of the FM 400 but the loss at 600CFM would certainly be less. Note that the loss increases approximately with the square of CFM.
    Hi Dave,

    I realised that the separators on the FM-400 would lose me some flow and incur more pressure drop, because they are in fact crude cyclones. You only have to watch the dust swirl to see that. What I didn't know was how much loss there would be.

  11. #70
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    Quote Originally Posted by jack620 View Post
    All correct. Here's a recent thread on how I built the DE. 2hp DE Build
    Hi jack 620. I tried to post this before, but it disappeared ....

    Obviously you used the Pentz design for your rotor housing, was this as an improvement on the housing of the 2HP source for the motor and rotor? What I'm asking here is whether I go the same route and use the motor and rotor from a FM-400 in a case of my own construction, or just unbolt the motor assembly and mount it fan down on top of SDD/Thein. I gather I would have to use the twin separators and filters to handle the throughput of the system. I could reasonably easily construct a transition elbow so that the filter assemblies are vertical.

    I'll have to print that plan of the rotor housing out, magnified, so I can study it. The method for drawing the spiral eludes me at the moment, but this is a method I understand. YouTube

  12. #71
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    Quote Originally Posted by jon542 View Post
    Obviously you used the Pentz design for your rotor housing, was this as an improvement on the housing of the 2HP source for the motor and rotor?
    Yes, it's the Pentz design. And no, I don't think it was an improvement on the original blower. The maximum static pressure was actually slightly lower than the original and the power consumption with no inlet/outlet restrictions was virtually identical. The configuration of my DE meant I needed to make a new blower if I was to convert it to pleated filters. So in my case it was worthwhile. In your case I wouldn't bother.


    Quote Originally Posted by jon542 View Post
    The method for drawing the spiral eludes me at the moment, but this is a method I understand. YouTube
    I show how I did it in my build thread. But again, I wouldn't bother. Building the blower is a LOT of work.

  13. #72
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    Quote Originally Posted by jack620 View Post
    Yes, it's the Pentz design. And no, I don't think it was an improvement on the original blower. The maximum static pressure was actually slightly lower than the original and the power consumption with no inlet/outlet restrictions was virtually identical. The configuration of my DE meant I needed to make a new blower if I was to convert it to pleated filters. So in my case it was worthwhile. In your case I wouldn't bother.




    I show how I did it in my build thread. But again, I wouldn't bother. Building the blower is a LOT of work.
    Hi jack620,
    That's good enough for me. The shape of the fan enclosure must be better than I thought.
    Noticed an interesting feature in the Pentz drawing of the Thein baffle, the height, according to the sketch, is the same as the diameter of the inlet pipe! Every single one I've seen was at least twice that. It would seem that the diameter is the same as the chip bucket! Hmmm .....
    I just reread your blower build, and something struck me, I might try a dryer drum for the case of a Thein baffle!

    Now to research the reticulation ..... Thanks very much for the advice!
    Cheers!

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