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  • Don Burch
    replied
    Re: Pentz Cyclone vs. Thien Separator

    Originally posted by Negative_Zero View Post
    Thanks to all who participated (and who do so in the future), I just thought it was the right time to respond to the suggestion that I should ask my question at the board for the Thien separator. It has been asked many times there and the response never gets to the level of this forum where there are so many different views held with such vigour. Instead the vibe at the Thien site is "give it a shot, it won't cost much if it doesn't work." I really wanted to get more views on it. I am going to give it a shot, and I will post my project once I get started. It is fun to be part of such a cool place.

    -Will
    Will,
    If you are going with a top hat arrangement, give some thought to the following.
    The whole idea of trash can separation came about mainly because of the limited waste capacity of shop vacs and unlimited hassle of bag changing in single stage collectors.
    The top hat configuration puts a bunch of mechanics on top of the waste bin, which will have to be removed to empty the bin.
    Think about punching a hole in the bottom of the barrel and setting the barrel on top of a stand with a drawer or other container for waste removal. The access to this opening must be absolutely air tight or the entire device will fail.

    Don

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  • Negative_Zero
    replied
    Re: Pentz Cyclone vs. Thien Separator

    Thanks to all who participated (and who do so in the future), I just thought it was the right time to respond to the suggestion that I should ask my question at the board for the Thien separator. It has been asked many times there and the response never gets to the level of this forum where there are so many different views held with such vigour. Instead the vibe at the Thien site is "give it a shot, it won't cost much if it doesn't work." I really wanted to get more views on it. I am going to give it a shot, and I will post my project once I get started. It is fun to be part of such a cool place.

    -Will

    Leave a comment:


  • michaely
    replied
    Re: Pentz Cyclone vs. Thien Separator

    I kinda liked the the 55 second video Will buried in the Thien forum link regarding "Vanwoodworker"'s running his cheapo Thien/'top hat'-modified Harbour Freight dust collector, pouring in sawdust into the inlet and leaving unconnected the output of separator baffle to visually show the apparent "success" in dust separation.

    http://www.youtube.com/watch?v=qVCqHsa_zq4

    I don't know how close this level of efficiency in finer dust separation comes to that of cyclone but barring some kind of Photoshop manipulation, but the video is impressive.

    Will, I'm with Scott of Rochester re this HF cheapo dc (seems to almost of point of pride how cheap it is - smiley) having a lot of fans.... given that you already have this dc, other owners are probably your best sort of advice on the various ways to squeeze out the most performance from it.
    What strikes me about the setup you considering is minimization of suction robbing twists and turns, the smoothness of the inlets and outlets of the type of separator and even....if I understand you correctly, that you are considering eliminating the filter media altogether and dumping the "fines" outdoors (this last, if possible, virtually gets rid of the "breathing in the smallest/most dangerous dust issue" and gives you a boost in system suction power)......

    I don't see dust collection quite like blade sharpening where there are dozens of ways and cost ranges from a couple of dollars to thousands, but there is room in duct collection for ingenuity and sweat labour (beyond creating a shop duct system) to get sufficient performance for chip removal and a breatheable shop environment out of single stage dust collectors......

    I'm not saying that a well made cyclone will not perform better than well modified single stage dc of equavalent power, but one the posters on sawmillcreek has a cute signoff quote: if I remember it correctly it goes "In theory, there is no difference between theory and practice, in practice there is".

    good luck

    michael
    Last edited by michaely; 05-01-2010, 09:56 AM. Reason: grammar

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  • Buster2000
    replied
    Re: Pentz Cyclone vs. Thien Separator

    Ultimately this is the question we have to answer. As with anything there is no ‘right’ answer; there are just too many variables here. What works for me, will not work for you.

    This discussion has been very instructive for me. I hope it has been for you too. Everybody has made some very good points, and I’m impressed with how far these discussion have come. I think as a group we understand how important air flow is to dust collection.

    On the other side, I think we still have a way to go. A cyclone is more than a bin with a funnel. While we can debate the true separating capacity, a cyclone is one of the few mechanical separators available to hobbyists. Further collecting chips is not the point of DC, a single stage collector does that very well. The point is to collect the smallest dust particles. Adding more air flow will grab them, but unless we have a good way to separate the particles (either throw filtering or mechanical separation) all we are doing is pumping them back into the shop.

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  • Claude in Kitchener
    replied
    Re: Pentz Cyclone vs. Thien Separator

    Originally posted by Don Burch View Post
    For me, effective dust collection is a health issue, not simply house keeping. I am in good health but recognize the hazards of this hidden natural carcinogen. Total cost of ownership is my focus.

    Don
    That is pretty difficult to argue with, Don, but compromises are made every day. I'd have a cyclone in a flash but my shop is not big enough or do i have the headroom. I have to make do with a less than ideal solution. The question is: how close can I come to cyclone performance and at what cost?

    Leave a comment:


  • North Woods Forman
    replied
    Re: Pentz Cyclone vs. Thien Separator

    I built the thien separator for a garbage can in my shop a couple months ago. I was sick and tired of cleaning my rigid shop vac filter every few minutes. I was a little sceptical but the project was so cheap I thought what have I got to lose. I have to say it does work fairly well. I get about 95% separation in my garbage can now. The other 5% that gets into the vacume is very fine powder that cakes the filter. To help with this issue I installed a shop vac filter bag over my pleated filter. Now when I shut the vac off I rap the side of it a couple times and most of the cake drops right off. THe only problem I have with it now, is the sides of my garbage can get sucked in a little when the vacume is running. I think I may have to reinforce the inside of my garbage can. I know my set up is not perfect dust collection, but for the twelve dollars the project cost me it was a huge upgrade to a good shop vac.

    Leave a comment:


  • Don Burch
    replied
    Re: Pentz Cyclone vs. Thien Separator

    Originally posted by Negative_Zero View Post
    Buster said:

    Actually, the main point of creating this thread was to try to quantify how much SP increase the most efficient Thien separator would introduce, and not to assume it was either zero or infinite.

    What Phil Thien has shown is that the options are not limited to cyclone vs. trash can, if the people using Thien separators are to be believed (and they seem to have no economic interest in deception). Typical reports seem to report separation of at least 80% and up to 95% of the dust and chips. That achieves most of what a cyclone does and probably enough for my needs.

    I should have posted a link to a "top hat" separator, as it represents a signicant improvement to reduce the SP increase of a Thien separator. What I am thinking of can be seen here and here. These modifications combine many of the attributes of the cyclone with the Thien baffle, and I think are likely to introduce much less SP increase, but I was hoping to get beyond mere guessing.

    I know how to measure separation efficiency (how much is in the barrel vs. how much there was to start). It seems that there is no simpleton's method to measure SP, so I am out of luck. This is perhaps why I could not find more reliable information to make the comparison.

    Thanks for everyone's thoughts,

    -Will
    Will,
    I went back to the net to look some more. I apologize for not reading more carefully in your original post.
    Your original example involves hacking up the traditional single stage unit to basically salvage the blower to place in a new assembly - a barrel or what ever.

    None of the discussions talk about what the single stage DC is really capable of. We know the manufacturer rates the machine based on what? So in Pentz's calculator, there is no adder for the basic single stage collector.
    So, is it reasonable to assume that a top hat design with baffle would not be any worse than a conventional single stage unit with respect to SP loss. And likely better because the barrel is rigid so any turbulence in the lower container due to bag movement is eliminated.

    So in light of no information to the contrary, I would have to say that the top hat design does not introduce any additional SP loss unless the order of flow has any relevance - single stage DC pushes stream to the separation chamber, top hat and cyclone suck the stream through the separation chamber. A stand alone knock out device, regardless of design, will add losses.

    In my opinion there remain weaknesses in this approach.
    1. the efficiency decreases as the drum fills. The solution offered for this is to know when to empty the drum.
    2. the design is not engineered.
    • to address particle separation. If you experience excessive carryover the solution offered for this problem is to simply add another knock out drum.
    • proper blower capacity for a given drum size is unknown
    • criteria for optimal blower performance are not considered. The fan manufacturers have some basic design considerations to minimize turbulence in the fan itself.


    For me, effective dust collection is a health issue, not simply house keeping. I am in good health but recognize the hazards of this hidden natural carcinogen. Total cost of ownership is my focus.

    Don

    Leave a comment:


  • Negative_Zero
    replied
    Re: Pentz Cyclone vs. Thien Separator

    Hi NTM,

    Thanks for sharing your experience. Can you post a photo of your separator? It sounds interesting.

    -Will

    Leave a comment:


  • NTM
    replied
    Re: Pentz Cyclone vs. Thien Separator

    While thinking about setting up my DC I went through thr conical versus cylindrical debate (Pentz vs. Thien). In reviewing these I came to certain conclusions:

    "The cylindrical unit is a good chip separator but may not be as good a dust collector as the conical version."

    Without some sort of mechanism to reduce the rotational radius of the airstream there may not be an opportunity to remove the smaller particles. As the airstream spirals down it encounters an ever diminishing cross section in the cone. The airstream changes in direction at an increasing rate; resulting in a decreasing cut point and smaller particles spin out of the airstream. I noticed this when I started using a Veritas® Cyclone Lid with my shop vacuum. Although the debris tank on the vacuum did not fill as fast, the cake on the filter built up at a similar rate as when the cyclone lid was not used.

    "The main benefit of the Thien design is to create a larger usable volume in the debris tank".

    Any debris which falls below the lower baffle through the drop slot cannot re-enter the air stream. The vortex is contained between the lower baffle and the lid. I have noticed with my Veritas® Cyclone Lid the vortex can scour and carry away material for over a foot into
    the debris tank.

    "The Thein unit is an effective and inexpensive method of turning a single stage dust collector into a dual stage collector."

    A dual stage system has the innate attribute of protecting the impeller from large and heavy debris particles. They drop into the debris tank before the airstream reaches the impeller. I think this is a good idea when one is going to use the dust collection system to vacuum the shop floor.

    My system is a network of 4" ppiping with blast gates connected 1200 CFM single stage collector. Between the network and collector I have a chip seperator consisting of a 45 gal. drum topped with a cylindrical cyclone chamber. It is Thienlike with a drop slot but the intake on mine enters horizontally rather than vetically through elbows. To mitigate or improve the cut size issue I replaced the filter bag with a pleated paper cylindrical filter canister. This cannister has an internal flapper to knock the cake into a disposal bag. It woks well for me. I don't have any reservations that its performance would be enhanced by a more expensive conical chip seperator.
    Last edited by NTM; 04-29-2010, 07:51 PM.

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  • Rod Sheridan
    replied
    Re: Pentz Cyclone vs. Thien Separator

    Originally posted by Negative_Zero View Post
    Buster said:





    It seems that there is no simpleton's method to measure SP, so I am out of luck. This is perhaps why I could not find more reliable information to make the comparison.

    Thanks for everyone's thoughts,

    -Will
    I guess you're not a simpleton like me.

    Get a bucket of water, a length of clear plastic tubing and and a tape measure.

    Mount the tubing in a straight vertical column with one end in the bucket of water, the other end connected to what you want to measure.

    Use the tape measure to measure how many inches of water column you have. (Note this works for vacuum, for pressure it just blows bubbles).

    Regards, Rod.

    Leave a comment:


  • Chris in Saskatoon
    replied
    Re: Pentz Cyclone vs. Thien Separator

    Originally posted by Claude in Kitchener View Post
    The tapered section's primary function is to funnel the particles into the waste container. Once the air stream turns to go out the outlet pipe no further significant separation occurs.
    I think there's a bit more to it than that, otherwise the slope of the tapered section wouldn't matter.

    If you look at the videos of the Clearvue cyclones in operation you'll see distinct streams of dust right down to the bottom of the tapered section, which makes me think that the air doesn't turn around right away.

    Lastly, check out the wikipedia link on cyclonic separation. From there:

    Air flows in a spiral pattern, beginning at the top (wide end) of the cyclone and ending at the bottom (narrow) end before exiting the cyclone in a straight stream through the center of the cyclone and out the top.

    Leave a comment:


  • Negative_Zero
    replied
    Re: Pentz Cyclone vs. Thien Separator

    Buster said:

    He seems to be under the impression that he will see no SP increase by introducing the separator, further he seems to believe that the Thein separator has a similar separating capacity as a cyclone.
    Actually, the main point of creating this thread was to try to quantify how much SP increase the most efficient Thien separator would introduce, and not to assume it was either zero or infinite.

    What Phil Thien has shown is that the options are not limited to cyclone vs. trash can, if the people using Thien separators are to be believed (and they seem to have no economic interest in deception). Typical reports seem to report separation of at least 80% and up to 95% of the dust and chips. That achieves most of what a cyclone does and probably enough for my needs.

    I should have posted a link to a "top hat" separator, as it represents a signicant improvement to reduce the SP increase of a Thien separator. What I am thinking of can be seen here and here. These modifications combine many of the attributes of the cyclone with the Thien baffle, and I think are likely to introduce much less SP increase, but I was hoping to get beyond mere guessing.

    I know how to measure separation efficiency (how much is in the barrel vs. how much there was to start). It seems that there is no simpleton's method to measure SP, so I am out of luck. This is perhaps why I could not find more reliable information to make the comparison.

    Thanks for everyone's thoughts,

    -Will

    Leave a comment:


  • Claude in Kitchener
    replied
    Re: Pentz Cyclone vs. Thien Separator

    Originally posted by Buster2000 View Post

    As for separation, this is basic. It’s the tapered section of the cyclone that selects out finer and finer particles. Smaller particles have no other reason to settle out of a fast air flow.

    Buster
    I don't think the tapered section is solely responsible for the fine particle separation. Otherwise, why have the straight section so big? And why have the opening to the outlet pipe positioned above the tapered section? Particle separation, large and small, occurs throughout the straight section. The length of the straight section allows several revolutions of the airflow before reaching the center outlet. This allows time for all the particles to slow down, from friction against the side of the cyclone, and fall out of the airstream. The tapered section's primary function is to funnel the particles into the waste container. Once the air stream turns to go out the outlet pipe no further significant separation occurs.

    The thien separator mimics this but is limited to a little less than one revolution of the container so, certainly, some small particles get to the outlet. The benefit is simple cheap construction and performance somewhere between a separator lid and a true cyclone.

    The OP original question is about SP loss and it's a valid and important question. If the loss is 4" and the improvement in the DC can make up for 1-2" of that loss then he is likely to end up with a system that works to his satisfaction.
    Last edited by Claude in Kitchener; 04-29-2010, 02:25 PM.

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  • Buster2000
    replied
    Re: Pentz Cyclone vs. Thien Separator

    Claude,

    I agree will makes a great case why he should use the Thein separator. In his situation this is a very good solution. He will have very little ducting from the separator to any machine. So SP drop from ducting will be very small.

    What I’m trying to impress upon him is that the Thein separator is not a cyclone. He seems to be under the impression that he will see no SP increase by introducing the separator, further he seems to believe that the Thein separator has a similar separating capacity as a cyclone.

    I think bill Pentz provides us with some pretty good boundaries for our expected SP. A trash can separator is at 4.5”, and a true Pentz cyclone is at 2.25”. Here is the basic Thein separator I’ve been looking at: http://www.cgallery.com/jpthien/cy.htm The Thein separator attempts to keep the air speed up by limiting the air flow to the top of the can, in a sense using a bit of cyclone separation (large particle will hit the wall, lose speed, and drop). But note, the act of turning the air and blasting it against the wall (even at a low angle) will introduce considerable amount of air friction. As well the area above the baffle is still open, another huge source of friction. Finally the air still has to take a 90 degree turn out of the lid. The Pentz cyclone on the other hand goes to pretty great lengths to reduce these types of air friction. So given this where do you think the SP will fall? Even it is half way between you’re still look at around 3.25”+ of SP from the separator alone, and in my opinion you’re going to be closer to 4” than to 3”.

    I would also like to point out the elimination of the flex hose (which for replacing 3’ of 6” flex with solid pipe is only 0.26” of SP), increasing the inlet size, and moving to a pleated filter are all things that can be done independent of the Thein separator. The advantage in my opinion is the reduction of larger particles reaching the filters. So it will take longer for us to see the effects of the filter plugging, and the reduction in air flow associated with that. Further, the convenience associated with it may outweigh any drop in air flow…

    As for separation, this is basic. It’s the tapered section of the cyclone that selects out finer and finer particles. Smaller particles have no other reason to settle out of a fast air flow.

    Buster

    Leave a comment:


  • Claude in Kitchener
    replied
    Re: Pentz Cyclone vs. Thien Separator

    Will, that is a well presented argument in favor of the Thien Separator.

    Maybe you should direct your question to Phil himself! Here is the contact info:

    [email protected]
    When E-Mailing, please include the word "SkipSpamFilter" in the body of your message to avoid our dreaded spam filter.

    If you find out any useful info from him please share it with us.


    I don't agree with Buster2000. I think a Thien separator is a worthwhile incremental improvement over a standard trash can separator. I wouldn't expect cyclone performance but much better performance than the standard trash can separator units. Trash can separators merely send the "dirty air" in along the edge of the can and suck "clean air" from the center with little happening in between to separate the dirt from the air. They count on the 180 degree turn in the air flow to separate the particles from the air stream. This works modestly well until the can fills above the 50% mark and then you get a much less separation.

    The thien baffle does not send the air stream towards the bottom of the can but along the circumference of the can. There is much greater opportunity for separation to occur and the baffle stops the scrubbing action so the container can be used nearly to it's capacity.

    The elimination of the flex hose, increasing the inlet size and the addition of a pleated filter (or direct venting outside without a filter) will go a long way toward overcoming the SP loss created by the thien separator.

    I have recently acquired a Delta 50-760 DC and plan to add a Thien separator. I have some ideas to improve the performance of the separator but my schedule is such that this will not happen until late summer or fall. If anyone is interested I will post the process and the results.
    Last edited by Claude in Kitchener; 04-29-2010, 08:06 AM.

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