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Thread: Which Air Filtration is Better??

  1. #16
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    David:

    Thanks for the theory. I know from experience that when I turn on both the Jet 2000 and Jet 1000B (which are opposite each other in the room to hopefully create circular movement), and if I leave them on for 2 hours or so on high, I get particle counts of small particles of approximately 20, and large particle counts of approximately 1-2. I don't know what a clean room has for particle counts, but this has got to be pretty stellar. Especially since my background particle count is usually about 500 particles here.

    So in my case, I'll leave the extra filter on for a few months, then take it off and not use the extra one again. I knew the units worked extremely well. It's just a shame they are so loud. And the original 2" thick filter in the unit needs to be replaced (it's overdue), so that may help some too.

    It seems like the number of air exchanges in Fred's Shophack unit would be dramatically lower than my two Jets (or even the single Jet 2000B) with that small fan. But his unit does clear the air much quicker, although my hunch is that his workshop is much smaller in cubic feet.

    Fred - how many cubic feet is your shop?
    Last edited by Alan Lightstone; 06-09-2021 at 5:01 PM.
    - After I ask a stranger if I can pet their dog and they say yes, I like to respond, "I'll keep that in mind" and walk off
    - It's above my pay grade. Mongo only pawn in game of life.

  2. #17
    Quote Originally Posted by Alan Lightstone View Post
    Well, sorry it took so long. Life got in the way.

    Today I ran the belt sander with only the Jet 2000 running. Two tests. One with the original filters on the Jet 2000, running at high speed. The other with the original filters with the addition of a 3M Filtrete MERV 14 / MPR 2800 filter taped to the intake grill.

    The measurements were done with my Dylos DC1100 meter, which, I believe measures 0.5 micron particles for its small particle setting per 0.1 cu ft of air (I could be wrong on the particle size. I'm going from memory here, but its the one set up for woodworkers to measure the smaller particles). My shop has a volume of roughly 18600 cu ft (very tall ceilings).

    Baseline particle count in workshop: 329 small particles (was a good day here. It usually is about 500.)

    Original Setup: Starting small particle count - 2121. Ending small particle count - 323. Time - 18 minutes.

    Additional MERV 14 filter added: Starting small particle count - 2131. Ending small particle count - 318. Time - 17 minutes.

    Sorry I couldn't get this into a table format. But the bottom line seems to be that the addition of the extra MERV 14 filter only decreased the time to get to baseline particle count by 1 minute, or a little over 5% reduction. Essentially no difference.

    Now, I haven't been able to locate a MERV 14 filter that I could use to replace the original filter. That might have a more dramatic effect. But, basically, I'm not impressed that this helps.

    Any other thoughts? Am I missing something, David?


    The DC 1100 Pro does 0.5. Interesting results which I believe corroborate what I found in my shop. First, a very powerful high CFM fan is required for filters to work quickly. Second, large filter area is critical. In my case my Jet scrubber has neither. Like me you would probably see those numbers decrease rapidly with a shop build unit utilizing 4x 20x20x1....that is if you have the space.
    Thanks,
    Fred

    Seasoned professional possessing unremarkable proficiency at innumerable skills.

  3. #18
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    I looked up the CFM for the Jet 2000. On high it's supposed to be 1700 cfm (insert grain of salt). Going through the new filter, the 2" stock filter, the reusable large interior filter, and the worthless looking filter on the outfeed side of it has to reduce the air flow somewhat.

    I couldn't find any specs on the Lasko 18" floor fan, but I would think that it would move far less air than that. Am I wrong there? It looks like their 20" high velocity fan may have solid CFM, but nowhere is it listed that I could find. Is the air resistance for filters placed in parallel much less than that in series like on my unit?
    Last edited by Alan Lightstone; 06-09-2021 at 6:44 PM.
    - After I ask a stranger if I can pet their dog and they say yes, I like to respond, "I'll keep that in mind" and walk off
    - It's above my pay grade. Mongo only pawn in game of life.

  4. #19
    My shop is 392 sq ft. I apologize Alan because after reading through my posts see I left out a detail. When I decided the test unit was a success, I installed a "Simple Deluxe 18" Industrial Wall Mount 3 Speed Commercial Ventilation Fan" in my production unit. This fan is rated 4000 cfm on the high setting. The Simple Deluxe does seem more powerful, but not much.....maybe 10-15%. At any rate having a cfm spec on the Simple Deluxe gives the ability to quantify circulation. I was also unable to find a cfm rating on the Lasko but the Dylos does not show a noticeable improvement with the Simple Deluxe.



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    Thanks,
    Fred

    Seasoned professional possessing unremarkable proficiency at innumerable skills.

  5. #20
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    Quote Originally Posted by fred everett View Post
    I was also unable to find a cfm rating on the Lasko...
    I've done some testing of the Laskos. They can move about 990 CFM with no filters attached. Putting a filter directly on the back of the fan reduces that, to about 500 CFM for a 2" thick generic MERV 8 and about 240 CFM for a DuPont 9100 (MERV 12). A 3M 1500 (also MERV 12) does much better than the DuPont with 380 CFM.

    Your setup will yield flow rates much closer to the unrestricted fan flow. The larger filter area is a big part of reducing the restriction but just as important, I suspect, is the plenum you have behind the fan. That spreads to flow out to use the full surface area of the filters. With the filter attached directly to the back of the fan the air flow is constrained mostly to a ring shaped area matching the fan blades.
    Beranek's Law:

    It has been remarked that if one selects his own components, builds his own enclosure, and is convinced he has made a wise choice of design, then his own loudspeaker sounds better to him than does anyone else's loudspeaker. In this case, the frequency response of the loudspeaker seems to play only a minor part in forming a person's opinion.
    L.L. Beranek, Acoustics (McGraw-Hill, New York, 1954), p.208.

  6. #21
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    Thanks for the info Fred. Sorry I missed you posting you shop size in the previous post, but knowing the ceiling height to tell the cu ft of your shop would help. Assuming 10 foot height (for no apparent reason), gives your shop about 3920 cu ft. or about 21% the air volume of mine. So actually, it would be a bummer if your setup didn't work much more quickly than mine, and it's great how quickly it works. I wish I could get that many air exchanges an hour in my workshop. I guess I miss the air systems in ORs. But the fan that you placed in the unit with 4000 cfm (before filters) would seem to be another matter entirely. Seems like what the explosion proof fan in my finishing room does. Sucks the door closed and seriously needs makeup air.

    How noisy is the Simple Deluxe fan? With no covering for the outtake, I would think it's quite loud. Ever measure that with something like an iPhone sound level app?

    As a practical matter, I can't imagine sizing yours up to be large enough for my workshop with one unit. Multiples would be needed, which would take up a huge amount of space (although with your 4000 cfm fan, maybe that's not true). I am fortunate that my two Jet units can clean the air down to very clean levels, and I think it does it in a reasonable time considering the large volume of air they have to process, but they are very noisy to say the least on high. Ear protection is needed.
    Last edited by Alan Lightstone; 06-10-2021 at 12:20 PM.
    - After I ask a stranger if I can pet their dog and they say yes, I like to respond, "I'll keep that in mind" and walk off
    - It's above my pay grade. Mongo only pawn in game of life.

  7. #22
    Quote Originally Posted by David L Morse View Post
    I've done some testing of the Laskos. They can move about 990 CFM with no filters attached. Putting a filter directly on the back of the fan reduces that, to about 500 CFM for a 2" thick generic MERV 8 and about 240 CFM for a DuPont 9100 (MERV 12). A 3M 1500 (also MERV 12) does much better than the DuPont with 380 CFM.

    Your setup will yield flow rates much closer to the unrestricted fan flow. The larger filter area is a big part of reducing the restriction but just as important, I suspect, is the plenum you have behind the fan. That spreads to flow out to use the full surface area of the filters. With the filter attached directly to the back of the fan the air flow is constrained mostly to a ring shaped area matching the fan blades.
    After posting last night I started wondering how much the enclosures play into these equations. My Jet AFS 1000 for example has a motor crammed into a small box with two filters behind it.....AND the exhaust slot is just 3.5" x 8.5" in size. I suspect 1000 cfm is with the blower alone sitting on a bench.

    The Lasko I initially tested is a 5 blade "cyclone" floor model. If that model performs at 990 cfm then Simple Deluxe has grossly overstated the performance (4k cfm) of the unit I purchased. If I had to bet, I'd bet Simple Deluxe overstated as I can not feel a 4 fold difference vs the Lasko.

    I'd be remiss if I didn't qualify my statements above as anecdotal. I have no doubt your calculations are correct David, and I know you know this, but with manufacturers overstating and/or publishing best case scenarios on cfm specs all hopes of coming to a mathematical conclusion seem lost....."garage in garbage out" as we say in IT.
    Thanks,
    Fred

    Seasoned professional possessing unremarkable proficiency at innumerable skills.

  8. #23
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    This thread has me wondering. And David please chime in if this would improve things.

    What if I built an add-on enclosure for the Jet 2000 with 20x25 filters on 4 sides (similar to Fred's design in a way). This would mean that the total surface area of filter material would go up from 500 sq in to 2000 sq in.

    Now it would bottleneck through the original 20"x25" (500 sq in) opening to get into the fan box. So does this do anything? And does keeping the present 20"x25"x2" stock filter help or hurt things in that scenario. I'm assuming that leaving the large internal washable filter is a good thing.
    - After I ask a stranger if I can pet their dog and they say yes, I like to respond, "I'll keep that in mind" and walk off
    - It's above my pay grade. Mongo only pawn in game of life.

  9. #24
    Quote Originally Posted by Alan Lightstone View Post
    Thanks for the info Fred. Sorry I missed you posting you shop size in the previous post, but knowing the ceiling height to tell the cu ft of your shop would help. Assuming 10 foot height (for no apparent reason), gives your shop about 3920 cu ft. or about 21% the air volume of mine. So actually, it would be a bummer if your setup didn't work much more quickly than mine, and it's great how quickly it works. I wish I could get my that many air exchanges an hour in my workshop. I guess I miss the air systems in ORs. But the fan that you placed in the unit with 4000 cfm (before filters) would seem to be another matter entirely. Seems like what the explosion proof fan in my finishing room does. Sucks the door closed and seriously needs makeup air.

    How noisy is the Simple Deluxe fan? With no covering for the outtake, I would think it's quite loud. Ever measure that with something like an iPhone sound level app?

    As a practical matter, I can't imagine sizing yours up to be large enough for my workshop with one unit. Multiples would be needed, which would take up a huge amount of space (although with your 4000 cfm fan, maybe that's not true). I am fortunate that my two Jet units can clean the air down to very clean levels, and I think it does it in a reasonable time considering the large volume of air they have to process, but they are very noisy to say the least on high. Ear protection is needed.
    My ceilings are just 8ft which forced me into the mobile cart configuration.

    You are correct, the Simple Deluxe (SD) is loud.....I added a VIVOSUN speed controller for that reason. After stripping out the VIVOSUN board, rocker switch and potentiometer, I hard wired the plug end of the SD to those components in a common box leaving the existing SD 3 speed mechanism in place at the other end, thus additional available settings if needed to control dB. I found a perfect balance with the SD set at high AND speed controller potentiometer at the lowest setting....an Android app called "Sound Meter" this get reads 37dB at 5ft. If I turn the potentiometer all the way up which is equal to the stock out of the box high setting I get 58db at 5ft. I wonder about the Sound Meter app because at 37dB the SD produces a very pleasant "white noise" but at 58dB the SD is very loud. At any rate I can deal with the increased noise for the short time it takes to lower the PM counts.
    Thanks,
    Fred

    Seasoned professional possessing unremarkable proficiency at innumerable skills.

  10. #25
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    I get 59dB at 5 feet from the Jet 2000 on high with the extra filter.

    Definitely loud.

    56dB dB from the Jet 1000B at 6 feet. Noticeably quieter, but not quiet.
    Last edited by Alan Lightstone; 06-10-2021 at 12:37 PM.
    - After I ask a stranger if I can pet their dog and they say yes, I like to respond, "I'll keep that in mind" and walk off
    - It's above my pay grade. Mongo only pawn in game of life.

  11. #26
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    Quote Originally Posted by fred everett View Post
    The Lasko I initially tested is a 5 blade "cyclone" floor model. If that model performs at 990 cfm then Simple Deluxe has grossly overstated the performance (4k cfm) of the unit I purchased. If I had to bet, I'd bet Simple Deluxe overstated as I can not feel a 4 fold difference vs the Lasko.
    Fred, it's likely that those two fans have noticeably different pressure vs flow characteristics. It's entirely possible for the SD to have really good free flow but not a lot of pressure to overcome restriction. So as soon as you put a filter on it the flow drops drastically.

    Actually. looking at the two fans gives us a hint of that. Compared to the Lasko, the blades on the SD are smaller in diameter but wider. The smaller diameter makes a larger gap around the blades, allowing more bypass when restricted.

    When I was testing the Lasko I tried adding a shroud around the fan. Free flow was reduced slightly, from 990 CFM to 980 CFM. With two filters though, the shroud increased flow from 170 to 190. The gap I was closing on that fan was a fraction of the gap on the SD.

    TL;DR: The 4000 CFM may not be a huge exaggeration, rather the design of the housing is not good for maintaining that flow under restriction.
    Beranek's Law:

    It has been remarked that if one selects his own components, builds his own enclosure, and is convinced he has made a wise choice of design, then his own loudspeaker sounds better to him than does anyone else's loudspeaker. In this case, the frequency response of the loudspeaker seems to play only a minor part in forming a person's opinion.
    L.L. Beranek, Acoustics (McGraw-Hill, New York, 1954), p.208.

  12. #27
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    Quote Originally Posted by Alan Lightstone View Post
    This thread has me wondering. And David please chime in if this would improve things.

    What if I built an add-on enclosure for the Jet 2000 with 20x25 filters on 4 sides (similar to Fred's design in a way). This would mean that the total surface area of filter material would go up from 500 sq in to 2000 sq in.

    Now it would bottleneck through the original 20"x25" (500 sq in) opening to get into the fan box. So does this do anything? And does keeping the present 20"x25"x2" stock filter help or hurt things in that scenario. I'm assuming that leaving the large internal washable filter is a good thing.
    Alan, to get more performance out of that unit you need to make a significant increase in CFM, at least 20% or so. Your plan may or may not be able to do that.

    But,if you could get enough increase to make a noticeable difference be aware that motor current increases roughly in proportion to CFM. Temperature rise increases with the square of current. Motor insulation ageing rate doubles for every 10C increase in temperature. The motor has most likely been selected by the manufacturer to have adequate lifetime when operated with the unit as designed. The motor probably has Class B insulation rated for 130C or a 90C rise above a 40C ambient. A 20% flow increase would cause a 44% temp rise increase. That could be as much as 40C, causing a 16x increase in ageing rate.

    If it ain't broke...
    Beranek's Law:

    It has been remarked that if one selects his own components, builds his own enclosure, and is convinced he has made a wise choice of design, then his own loudspeaker sounds better to him than does anyone else's loudspeaker. In this case, the frequency response of the loudspeaker seems to play only a minor part in forming a person's opinion.
    L.L. Beranek, Acoustics (McGraw-Hill, New York, 1954), p.208.

  13. #28
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    Quote Originally Posted by David L Morse View Post
    According to the spec sheets both the Grizzly and Shopfox are made in China.

    https://cdn0.grizzly.com/specsheets/g0738_ds.pdf
    https://d27ewrs9ow50op.cloudfront.ne...s/w1830_ds.pdf

  14. #29
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    Quote Originally Posted by David L Morse View Post
    Alan, to get more performance out of that unit you need to make a significant increase in CFM, at least 20% or so. Your plan may or may not be able to do that.

    But,if you could get enough increase to make a noticeable difference be aware that motor current increases roughly in proportion to CFM. Temperature rise increases with the square of current. Motor insulation ageing rate doubles for every 10C increase in temperature. The motor has most likely been selected by the manufacturer to have adequate lifetime when operated with the unit as designed. The motor probably has Class B insulation rated for 130C or a 90C rise above a 40C ambient. A 20% flow increase would cause a 44% temp rise increase. That could be as much as 40C, causing a 16x increase in ageing rate.

    If it ain't broke...
    Wow!! Never knew that. Good advice. I'm done. It is what it is. Lots of cu ft of airspace in my workshop. Glad I have two units, though.
    - After I ask a stranger if I can pet their dog and they say yes, I like to respond, "I'll keep that in mind" and walk off
    - It's above my pay grade. Mongo only pawn in game of life.

  15. #30
    Quote Originally Posted by David L Morse View Post
    Fred, it's likely that those two fans have noticeably different pressure vs flow characteristics. It's entirely possible for the SD to have really good free flow but not a lot of pressure to overcome restriction. So as soon as you put a filter on it the flow drops drastically.

    Actually. looking at the two fans gives us a hint of that. Compared to the Lasko, the blades on the SD are smaller in diameter but wider. The smaller diameter makes a larger gap around the blades, allowing more bypass when restricted.

    When I was testing the Lasko I tried adding a shroud around the fan. Free flow was reduced slightly, from 990 CFM to 980 CFM. With two filters though, the shroud increased flow from 170 to 190. The gap I was closing on that fan was a fraction of the gap on the SD.

    TL;DR: The 4000 CFM may not be a huge exaggeration, rather the design of the housing is not good for maintaining that flow under restriction.
    I beleive you've touched on a valid point regarding flow characteristics. At full power my fan creates discernable air flow in all corners of my shop. At twice as long as it is wide, my shop probably lends itself to a vortex like flow with the air filter pointing at the ceiling.
    Thanks,
    Fred

    Seasoned professional possessing unremarkable proficiency at innumerable skills.

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