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Thread: Dust Collector too small (HP) and locating in garage create dust on cars?

  1. #46
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    Quote Originally Posted by David Kumm View Post
    Cyclone design is pretty similar to Oneida and Pennstate. Downside would be the motor and perhaps the filter material. Dave
    Thanks Dave.

    I own a Grizzly table saw and 8" joiner. I am happy with them. The cost of their DCs seems somewhat high. I think of Grizzly as a good bang for the buck manufacturer. I wouldn't pay that much for their 5 HP DC when I could pay a few hundred more for the Oneida Smart Pro or save a bunch and get the Clear Vue 1800.

    I am torn between the Clear Vue and the Oneida Smart Pro. A less expensive 5 HP Oneida would be acceptable but I'm worried about the Oneida Pro 2000, it has an 8" inlet port compared to the Smart Pro with a 7" input port. I am concerned that reducing 8" to 6" will be a problem. If I shouldn't worry about 8" -> 6" please let me know. I could save about $1000 and get the 5 HP Oneida Pro 2000.

    I have nothing against the Clear Vue, except it's "home-made" looks. Please don't take this the wrong way, it's a flaw in my personality. I really wish I could accept the "home-made" look as it would save me about $1000, but I will have to look at the DC every time I pull into my garage. I know, it makes no sense, I'm weird. I'm not dismissing the Clear Vue, so many people love it and that says a lot! And the $1000 savings would buy another nice tool.

  2. #47
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    Todd, buy whatever you prefer but the smart system doesn't warrant the $1K extra. I see the 8" inlet as a plus for the ability to upgrade later. I would save the money and spend a few bucks of it for spiral pipe and large radius fittings rather than PVC. As I have said before I would get the three phase motor and put on my own vfd. Motor will pull more air than the single phase version although you don't need that. You will have soft start and won't have to worry about too many starts per hour being hard on the capacitors. You can slow the rpms down a little when you don't need the flow and quiet things down. The 3 hp would likely be fine but for $200 extra and the hepa option thrown in the 2000 is a pretty good deal. Of course with my tendency toward used I would look at the Dust Vent industrial on ebay with all kinds of Norfab pipe for $1200. The vfd will set you back another $500 or so. In the straight 5 hp 15" impeller configuration the clearvue cyclone is hard to beat if looking just at fine dust separation for the price but a three phase option isn't available at this time. Clear as mud. Dave There is also a clear vue 5 hp with extras on CL at $1000.
    Last edited by David Kumm; 03-20-2012 at 12:30 AM.

  3. #48
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    Todd, I would love to have your problem.

    It looks to me like the 5 HP Grizzly is more expensive than the 5HP Pro 2000? $2200 vs. $2500 excluding shipping? Oneida shipping is more and there are some options to add to compare apples to apples.

    I would be torn between these two if these were my top choices. Just to make your decision harder, since I am not fortunate enough to have your problem...The Oneida has the HEPA filter which is great, but I would think that it would tend to plug fairly quickly. The grizzly filter is pretty good and there is twice the cloth area. Air:cloth (A/C) ratio is a concern especially when you have gotten out all of the big pieces with the cyclone. People debate about putting cyclones before baghouses (think large after filters with compressed air pulse cleaning) because all the small particulate that comes out of the cyclone can embed in the filter media and there are no larger particles to help knock it out or to cover sections of the media to prevent it from blinding. If the A/C is too high, small particles can be forced too far into the filter media and cause it to blind because it can't be cleaned. The way around this is a lower A/C (reduced velocity through the filter media) to prevent the particles from embedding too far into the material. The Oneida A/C would be at about 9:1 (1000 CFM/110 ft2) and the Grizzly would be at about 4.4:1 (1000 CFM/226 ft2). If I were designing new, I would try to get the customer to buy something in the 3:1 A/C range.

    Its late and maybe I am reading too much into it. I know in industrial systems, you would not put a HEPA filter after a cyclone, unless you want the Maintenance staff to have job security. You will get very good particle filtration through the HEPA, but if it blinds over (blinding meaning that you will not be able to clean it), your outlet SP on the blower will be increased causing you to lose CFM and reduce capture at the hoods. This can launch additional dust into the air and create a dusty shop until you replace the filter. Maybe it is not an issue with home shop systems or this particular system. Maybe others have some experience with this setup. My experience is mostly industrial. I only have a single stage unit at home with a cartridge canister filter. I notice a huge increase in flow when I take the canister off and clean it out with the vacuum, then replace it. I'm aware that the filter cake actually can improve collection efficiency, but blinding is a separate issue.

  4. #49
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    Mike's point is good about the filters especially if you are discharging into the garage rather than the shop. Kind of eliminates the need to hepa filtration. Dave

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    The story goes to the effect that if you have a high performing cyclone that HEPA filters last well - there doesn't seem to have been kick back to the effect that blinding is an issue on the ClearVue forums or here. But who knows for sure.

    Interesting this business of backwards inclined impellers, and variants of them.

    Looking closely at the picture of the impeller in the spec sheet linked via 'technical specs' at the bottom of this page http://tiny.cc/bk1gbw it does have more blade depth and backwards curve than a typical BC - although it's more like an adaptation of a BC impeller than a typical shrouded BI item like no. 4 here: http://www.cincinnatifan.com/blower-wheels.htm Ditto on the 5HP unit, although it looks very like it could be the same impeller in the picture so it may or may not be an exact representation.

    Cincinatti get about 1,000CFM from 2HP at 8in WG at 3,450RPM, so the figure in the curve of 785CFM at 8in off 2HP looks do-able with a BI impeller. It's not going to get to the 1,000+CFM or so at 15in WG of a 5HP unit, especially not with a dirty filter on top, but it's probably going to do a lot better than a BC.

    Bill P it seems did some playing with BI impellers, but reportedly ran into problems with stalling and buffeting at high pressure drops/lower air speeds. Looks like O found a way around it, at least at this size anyway - maybe that's why it look a bit different to the usual BI.

    There's a write up on the basic pros and cons of the various (traditional) types here: http://tiny.cc/t70gbw

    ian
    Last edited by ian maybury; 03-20-2012 at 11:04 AM.

  6. #51
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    The Oneida wheel looks like the Cincinnati Fan Type 6, backward curved radial fan. I can't imagine Oneida has a special wheel design proprietary to them. They are likely buying the wheel and assembling it. A lot goes into the wheel construction and testing. There are many fan companies that make their living doing only fans (Cincinnati, Twin City, New York Blower, Clarage, Robinson, etc.). Its doubtful that a manufacturer serving a nitch retail market of hobbyists in the woodworking industry has spent the R&D $$ to develop a new fan.

    I think a typical BI would be more efficient. The backward curved radial is probably somewhere between the radial type and BI, probably closer to the radia type, if I had to bet.

    Ian, its probably that no-one actually knows how the SP builds. The low use of the home shop collector and variation in dust particulate size probably helps the situation. Also, with the low use rate, there would be a slow build up and maybe hard to notice a reduction in volume because you get used to it. The only time I have ever seen HEPA filters in industry is on the outlet of a baghouse. Ther may be some application on the outlet of a cyclone, but I would imagine the cyclones are dealing with a very high percentage of larger particulate. The baghouse is usually filtering down to 99.9% on 1 micron. A cyclone will not do that in the size cyclones available to home shop users, regardless of the claims. CV has done some lab tests, but these are lab tests at specific conditions. If your flow and dust particles are different, the cyclone efficiency will be different. Even with the baghouse, the systems are almost always equipped with a divert damper to allow the facility to vent to atmosphere and bypass the HEPA filter bank. This is common practice in the summers for most facilities. The HEPAs are there to reduce gas costs associated with make-up air in the winter. They do not want to replace plugged HEPA filters in the Summer months.

    My home furnace does not have a HEPA filter. It has a pleated furnace filter that still plugs every few months. I may be wrong, but I would venture that the return air to my HVAC unit has lower PM than the effluent from a cyclone that is connected to a woodworking machine (especially a sander).

    Pricewise, I might ask Oneida if they can furnish the unit with a different after filter. I can't recall what the filtration range should be, but my understanding is that the very small stuff is not a problem. There is a range of particulate size that gets breathed in, but does not come out. You want the coarsest filter that gets the range that you need. Any finer, and you are adding needless expense, potential blinding problems, and could cause performance issues. If you loose flow and can't get the dust in the hood, it doesn't matter how good the collector filters.
    Last edited by Michael W. Clark; 03-20-2012 at 12:13 PM.

  7. #52
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    Michael and Ian, I've been studying- liberal use of the word- the fan numbers over at the CF site and struggling with how to compare. The BI fans seem to deliver less cfm at much lower hp than the typical blade for the same size. I'm looking mainly at the 14-16" range and trying to stay within the limits of the 5 hp motors at 4-5" sp as I suspect the motors are sized to be fully loaded at about that resistence. I agree that the fans are likely sourced elsewhere. Given the number of sizes it would seem unlikely that they are all specially made so there should be some comparables out there. It looks like the BI fans have a range where they deliver most efficiently and then taper off at higher rpms or higher airflow so that overamping the motor is less of a problem. Anyone who knows about air delivery at different levels of resistence for different types of fans can chime in here and help me to understand the trade offs. Dave

  8. #53
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    David,
    Can you provide a link to the page?
    Thanks,
    Mike

  9. #54
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    Quote Originally Posted by Michael W. Clark View Post
    David,
    Can you provide a link to the page?
    Thanks,
    Mike
    I'm sort of a Klutz on links but if you go to the Cincinnatti site and go to fans all types come up. I look at PB fan catalog and the info is part of the catalog. Hope that helps. Dave

  10. #55
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    My latest info is that Oneida does indeed cast their own blades. The wider blade they use allows for more airflow at low SP but causes the cfm to drop off more quickly at high resistence than more narrow ones. I can't verify any of that as I'm in over my head. seems that the design of the blower housing also impacts the airflow efficiency. I have also been told that the industrial type blades like those from Cincinnatti fan are a step up in both quality and efficiency from the hobby level ones used in DCs we buy. Again not verified by multiple parties- yet. Dave

  11. #56
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    I didn't look at BI impellers until this thread came up David as they typically are ruled out for dust system use. Like in most things we have a tendency to think in terms of clear distinctions when we refer to this sort of stuff, but in practice it starts to look like there are what you could almost call hybrid impellers about - ones as you say Michael that are half way between BC and full BI.

    It's a bit less marked than on the Oneida, but even the blades on the ClearVue impeller http://www.clearvuecyclones.com/supp...-impeller.html are curved along their full length - unlike the more traditional BC which just has the tips set back a bit. Which latter basically trades a little less performance (especially at higher pressures) for a little less noise. (see the pictures and tables in the Cincinatti Fan SPB catalogue)

    Even though they look fairly similar (BC and BI) they potentially operate very differently - so heaven knows what's going on in a hybrid. Radial and BC types impart kinetic energy to 'fling' packets of air that the inlet has deposited between the blades out the exhaust, whereas on the BI type the blade is described as 'flying' - as functioning like an aerofoil. Which is presumably why when the angle of attack get too steep at low airspeeds on a BI impeller it stalls. They are also much more speed/RPM specific in their design.

    The aerofoil function probably also explains the use of a shroud/annulus to bridge between the tips on the traditional BI impellers - as well as helping the tall blades structurally it probably reduces tip losses. (like the winglets on the tips of the wings of the latest jets)

    The next step in performance it seems actually uses a true aerofoil section blade version of the flat plate blade in the BI, but is even more sensitive in terms of its only functioning within an even narrower range of conditions.

    The Kruger technical bulletin linked at the bottom of my post above (or another piece I read recently - can't remember for sure) says that for radial and BC type fans the clearances between the impeller and the fan housing don't (within reason) much influence fan performance - but that the situation is different for BI fans which need to run tighter clearances.

    It also confirmed the two disadvantages attributed to BI fans before - a risk of stalling at low airspeeds/with too many blast gates closed and a tendency to get clogged with shavings if they are not dropped out before the fan.

    I suspect that as before Michael that cyclone performance on the fine dust is indeed a bit of a variable feast, and that it probably depends on stuff like phases of the moon and so on. Or at least that there will be a particle size range and weight, and inlet velocity and turbulence that's going to suit a specific cyclone layout best. That as you say (and as I've seen written elsewhere) that very small changes in the set up and even build may well make quite large differences to retention performance. My system is set up as you describe - opening a blast gate allows it to exhaust outside. I've not run it that mode yet though.

    It seems by the way (again reportedly) that the HEPA standard defines retention performance at a particle size of 0.3 micron because this is the size that is most difficult for the body to deal with....

    ian
    Last edited by ian maybury; 03-20-2012 at 4:16 PM.

  12. #57
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    Maybe they do have their own design. I did not see anything about AMCA on their website, maybe I missed it. Many industrial fan manufacturer's are members of AMCA (Air Movement and Control Association). They have specific test standards for fan performance. If a company is not a member of them, it doesn't mean their product is not good or is necessarily inferior. It just means the performance was developed with a different test method and may not be comparing apples to apples with the performance of AMCA fans. At the end of the day, energy is conserved and it takes "X" amount of eneryg to move a volume of air, at a given rate, across a system with a known resistance. The mechanical efficiency of the fan wheel will reduce the BHP required.

    David,I would think you would want the CF that is rated at about 9-10" SP. On page 9, there are several options for the 3450 RPM direct drive model in the 1500 CFM range (8" duct at 4300 FPM).

    I think Oneida probably makes a great product, and definitely like that it is Made in the USA. They would be one of my first ones to consider if buying new. What about Penn State Industries? I know a few who have their cyclones and are quite pleased with them.

    Todd, I feel like I am living vicariously through you today.

    Mike

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    http://www.cincinnatifan.com/fan-selector.htm is how I found the "interesting fans". I plugged in 1000 CFM and 10 for SP (figuring 4" for the piping in the OP's setup which is long but not unusual plus 3-4" for the cyclone plus 1-2" for the filter plus some amount of me not knowing things, 10" seemed relatively safe anyway - I don't claim correctness on anything here).

    At 8" the suggested fans are quite a bit different .. and at 100CFM @12" you get some really interesting results.

    The PB series seems to be the most overlapping with ~many? of what I can figure commercial cyclones use, the HP series is.. interesting.. (practical? maybe not, I don't know enough to say.. interesting yes )

    I left that list even more confused than I started with though

    It looks like you can (in theory) get 12" of pressure with a 23" wheel at ~2.5 HP (steady state, not counting spinup), I suspect that there are stall and spinup issues at that size though... and its the most expensive fan and you need a big honkin motor just to get it to spin up in direct drive mode, and well... the SP we're interested in isn't even on its curve (looking at the HP-10F23 for example). More "useful" looking is perhaps the HP-4A and HP-4C models, again we're below the interesting pressure curve so its possible that they don't even work well at the lower pressure. The recommended model in that line would probably be something like the HP-6B, but then you're well back into 5HP range.

  14. #59
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    Hi, in my post I calculated that the OP needed 1000CFM at 4" WC.

    Using the Cincinnati fan catalogue you can select a fan that requires .94HP for that task.

    As you noticed from the Oneida cyclone curve, the cyclone fan at 2 HP was capable of much more than the OP needed.

    If you select a fan with really poor efficiency you need a big motor, however that's not what Oneida do.

    The Oneida cyclone the OP purchased was more than adequate for his needs, unfortunately instead of doing the calculations, he sold it because he was getting anecdotal evidence that you need at least 4 HP.

    As I indicated previously, only the fan designer needs to know the HP, it's a useless specification as can be seen from the selection of a good versus poor fan design.

    Regards, Rod.

  15. #60
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    Rod, since the CF ratings are straight fan curves, how much did you add to the 4" for cyclone and filter loss? Dave

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