woodshop nerdery youtube channel

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woodshopnerdery
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Re: woodshop nerdery youtube channel

Post by woodshopnerdery »

algale wrote: Fri Aug 13, 2021 8:14 pm Interesting video. More small 0.3 micron particles outside in fresh air than when using the belt sander insider connected to an underpowered dust collector with a 2.5 micron filter bag and a homemade ambient air cleaner. I would have thought the inside air would have been worse. Makes me wonder whether the bigger dust collector, finer filter media race is perhaps a losing proposition.
Good points. Thanks for watching the video. I would like the air in my garage to be even cleaner than it is. But hat would require a canister HEPA filter, which would require a larger blower and motor, and would require a cyclone pre-filter to keep the canister clean. Believe me, if the numbers ever get any worse, I would be looking for a way to bring in a better system. But I take you point, the canisters require both a stronger blower and a cyclone pre-filter of some sort, so it is sort of a three way "race."
woodshopnerdery
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Re: woodshop nerdery youtube channel

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I have done similar tests myself in the past. Sometimes outdoor air is cleaner than in my shop and other times it is the opposite. Bottomline is it depends on where you live because outdoor air pollution in this particulate size includes smog, diesel exhaust, tobacco smoke, soot, etc. It also varies a lot day to day and hour by hour. When landscapers run their leafblowers nearby my outdoor air quality is through the roof, but my indoor levels are significantly lower. His argument of the outdoors being his baseline is NOT a good argument. Many of us strive to have cleaner IAQ than what is outdoors since most of us spend the majority of our time indoors and we live in a polluted area. Whether or not someone wants to spend the money on a HEPA cartridge filter is dependent on their bank account and how much they value their own health and lungs. A HEPA cartridge filter WILL have greater collection efficiency in the 0.3um particle range than a bag filter.
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I agree that a HEPA cartridge is needed to get more of those sub micron particles. And yes I would like the air to be cleaner than it is. I was pleasantly surprised it was not massively worse.

But I think you would also agree that if I put a HEPA cartridge on my 1HP system it would not work. It would push the CFM down very low and as the filter filled with dust, even lower. This could POSSIBLY (maybe) actually make the air worse because the system is not bringing in as much air and less volume of air is getting cleaned. I would guess that a HEPA cartridge would need minimum 1.5HP AND a first stage separator.

BTW - I think I mentioned to you I liked the looks of the Onieda Mini Gorilla. Used one up for sale in my area but still above my budget. If I am lucky it will sit long enough for the seller to lower the price to within my range. Fingers crossed!
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Re: woodshop nerdery youtube channel

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woodshopnerdery wrote: Fri Aug 20, 2021 10:25 pm Good points. Thanks for watching the video. I would like the air in my garage to be even cleaner than it is. But hat would require a canister HEPA filter, which would require a larger blower and motor, and would require a cyclone pre-filter to keep the canister clean. Believe me, if the numbers ever get any worse, I would be looking for a way to bring in a better system. But I take you point, the canisters require both a stronger blower and a cyclone pre-filter of some sort, so it is sort of a three way "race."
I must have missed something.

If the pleated cartridge filter has many times the surface area of a bag, why would you need a larger blower motor?

Why would a cyclone separator be required? Wouldn't the large pieces fall into the bag on the bottom?

Looking at https://wynnenv.com/, I don't see anything about requiring separators or larger motors.
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Re: woodshop nerdery youtube channel

Post by rlkeeney »

I have been using a Clean Stream Filter in my shop vacuum for several years. I would never go back to the old disposable filters. It makes a massive difference for sanding.
Clean Stream Pro Hepa Filter.resized.jpg
Clean Stream Pro Hepa Filter.resized.jpg (136.57 KiB) Viewed 3284 times
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woodshopnerdery
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Re: woodshop nerdery youtube channel

Post by woodshopnerdery »

rlkeeney wrote: Thu Aug 26, 2021 5:12 am I must have missed something.

If the pleated cartridge filter has many times the surface area of a bag, why would you need a larger blower motor?

Why would a cyclone separator be required? Wouldn't the large pieces fall into the bag on the bottom?

Looking at https://wynnenv.com/, I don't see anything about requiring separators or larger motors.
As far as I understand it, the issue is that all filters clog eventually. When they become very clogged the air flow drops significantly. The less air moving through the system the less dust it collects. Pleated filters add more surface area and therefore have a higher initial airflow than felt bags of equivalent micron rating. However, the smaller the particle the filter traps, the less air flow it allows, even when new. So even a new pleated HEPA filter will have less flow than a 1 micron pleated filter of the same dimension. So to get the same air flow through the system with a more efficient filter, you need a more powerful motor.

Since HEPA filters trap more dust they become clogged faster and the air flow drops faster. So pleated HEPA filters have to be cleaned more often to maintain air flow. It is not easy to fully clean pleated filters. The common solution is to add a cyclone separator to extend the time between filter cleanings. Note cyclones separate large particles, but also separate some of the particles that would clog the filter. However, cyclones add some air friction to the system and air friction means less air velocity. So to maintain the same air flow after adding a cyclone, you need yet again an even more powerful motor.

So in my opinion, I cannot simply add a canister to my little system. I would need a major upgrade including a cyclone and a more powerful motor. Jet, Laguna and Oneida have 1.5 HP cyclone systems with HEPA filters. If I make a change to my system, it would be to get or make something like that.
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Re: woodshop nerdery youtube channel

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woodshopnerdery wrote: Wed Sep 08, 2021 9:11 am As far as I understand it, the issue is that all filters clog eventually. When they become very clogged the air flow drops significantly. The less air moving through the system the less dust it collects. Pleated filters add more surface area and therefore have a higher initial airflow than felt bags of equivalent micron rating. However, the smaller the particle the filter traps, the less air flow it allows, even when new. So even a new pleated HEPA filter will have less flow than a 1 micron pleated filter of the same dimension. So to get the same air flow through the system with a more efficient filter, you need a more powerful motor.
Why would you have "identical" surface area for a HEPA filter compared to a non-HEPA 1 micron pleated filter? Yes, HEPA filters can capture much smaller particle sizes than traditional pleated filters, but to compensate for the restrictions of a HEPA filter they typically have much more surface area in comparison to a standard filter. I would argue that a properly selected HEPA filter should be far less restrictive than typical standard filters it replaces because they often have vastly superior filter area in the same form factor. I would honestly expect your DC airflow to improve by switching to a HEPA filter from a non-HEPA filter.
woodshopnerdery wrote: Wed Sep 08, 2021 9:11 am Since HEPA filters trap more dust they become clogged faster and the air flow drops faster. So pleated HEPA filters have to be cleaned more often to maintain air flow. It is not easy to fully clean pleated filters. The common solution is to add a cyclone separator to extend the time between filter cleanings. Note cyclones separate large particles, but also separate some of the particles that would clog the filter. However, cyclones add some air friction to the system and air friction means less air velocity. So to maintain the same air flow after adding a cyclone, you need yet again an even more powerful motor.
So, the assumption here is that HEPA filters have identical filter area again when this is often not true. IF a HEPA filter has significantly more surface area, i.e. more pleats than a standard filter then it won't clog faster than a non-HEPA filter necessarily. Cyclones prolong filter life of HEPA and non-HEPA filters (both have to be cleaned), but they do restrict airflow (10-20% in my experience). Whether the drop in airflow is noticeable largely depends on your DC system and ductwork. There are different specs to consider for a DC system, but the main one in a ducted system is trying to maintain at least 4000fpm on horizontal ducting. This is because when the air stream drops below 4000fpm the size dust particles often found in woodworking can drop out of the airstream and settle on the bottom of the those horizontal runs. Taking ductwork apart to clean it out is a real PIA so you want to minimize any dust settling out inside the ductwork. IF you have no ducting, i.e. using short hoses only, you can actually tolerate some drop in airflow from a cyclone and for the most part not compromise dust collection at the tool because you are not limited by that 4000fpm general rule. It is also possible to mitigate airflow restrictions due to a cyclone by putting more than one in parallel. It costs more to go parallel, but that can be mitigated with low cost Chinese cyclones.
woodshopnerdery wrote: Wed Sep 08, 2021 9:11 am So in my opinion, I cannot simply add a canister to my little system. I would need a major upgrade including a cyclone and a more powerful motor. Jet, Laguna and Oneida have 1.5 HP cyclone systems with HEPA filters. If I make a change to my system, it would be to get or make something like that.
I am not trying to talk you into a cyclone or a HEPA filter here, but just give you some perspective based on my own experience. I chose to run a cyclone and did enough airflow measurements to convince myself that I am better with it than without it in my system. I also chose to run HEPA filters in my system because my health is important to me. However, these choices largely didn't affect my dust collection ability because my shop is too small for ducting so I am using short, high quality hoses (low SP drop). I considered ducting my shop, but I would have had to go through the attic with it and it would have required at least $2k between cyclone, DC and ductwork. I just can't justify that expense for myself right now, so what I have works, albeit on a much smaller scale. I can't comment on your specific DC system or your shop's needs, but I can certainly understand the cost factor involved. IF you are doing ductwork and have a lower powered DC it can certainly necessitate needing a larger DC if you add HEPA and cyclone to it.
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Re: woodshop nerdery youtube channel

Post by JPG »

So thee disagreed then agreed.

Good points in between!
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woodshopnerdery
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Re: woodshop nerdery youtube channel

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RFGuy wrote: Wed Sep 08, 2021 10:00 am So, the assumption here is that HEPA filters have identical filter area again when this is often not true.
Yep, I made the assumption and clearly stated that assumption in my text for the sake of highlighting a very important point. That is, that particle filtration efficiency impacts air flow rates per area unit. But you are correct that a pleated HEPA canister filter does not necessarily expose the same surface area as a 1 Micron Pleated Canister. In fact the HEPA filter could have less surface area. It could more, it could be less, it could be the same. It totally depends on the specs of each specific unit.

I stand by my conclusion that my system will not work by simply adding a HEPA canister. I look to the experts who design products for Oneida, Laguna, Jet and others. I cannot find a commercially made DC that includes a HEPA canister filter which does not also include a Cyclone separator. I think there is probably a good reason for that. There is also a reason that these reputable manufacturers put no less than a 1.5 HP motor on these systems. Most likely to help overcome the air friction introduced by the cyclone.

Personally, I'm not investing in a HEPA cartridge without a cyclone. If I make any changes at all it will be along the lines of the following designs all of which have a more powerful motor than my current system.

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Re: woodshop nerdery youtube channel

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woodshopnerdery wrote: Wed Sep 08, 2021 5:53 pm Yep, I made the assumption and clearly stated that assumption in my text for the sake of highlighting a very important point. That is, that particle filtration efficiency impacts air flow rates per area unit. But you are correct that a pleated HEPA canister filter does not necessarily expose the same surface area as a 1 Micron Pleated Canister. In fact the HEPA filter could have less surface area. It could more, it could be less, it could be the same. It totally depends on the specs of each specific unit.

I stand by my conclusion that my system will not work by simply adding a HEPA canister. I look to the experts who design products for Oneida, Laguna, Jet and others. I cannot find a commercially made DC that includes a HEPA canister filter which does not also include a Cyclone separator. I think there is probably a good reason for that. There is also a reason that these reputable manufacturers put no less than a 1.5 HP motor on these systems. Most likely to help overcome the air friction introduced by the cyclone.

Personally, I'm not investing in a HEPA cartridge without a cyclone. If I make any changes at all it will be along the lines of the following designs all of which have a more powerful motor than my current system.
It is possible that I misunderstood your comments on filters here because of your terminology. Unless you explicitly stated "HEPA" filter then I assume it is not, so for example when you say "pleated filter" I don't assume that this is a HEPA filter. Okay, with that out of the way, my interpretation of your previous post is you were comparing a HEPA filter to a non HEPA filter, BUT you restricted it to be of the same "dimension". For me, this is like comparing apples to oranges. Yes, the material in a HEPA filter can be more restrictive than the same amount of surface area of a non HEPA filter, but that is really irrelevant because HEPA filters usually have significantly more surface area of filter media than an equivalent non HEPA filter of the same overall form factor in the system. That is what I was trying to point out on your prior post. Yes, a HEPA filter has more restrictive filter media, but because of the much greater surface area, they usually are less restrictive overall in the system because of this. As a result, I don't see how a HEPA is going to clog up faster than a non HEPA filter. So, you don't need a more powerful motor because you switched to HEPA in my opinion. Of course, HEPA filters ARE more expensive than non HEPA filters so many owners want to protect that investment and as a result it is common practice to install a cyclone in the DC to prolong the life of the filter. The addition of a cyclone CAN offer enough restriction to limit the effectiveness of a DC system. However this is often only a factor when the DC system is being used with ductwork as the over-riding requirement is maintaining that 4000 fpm airstream on horizontal runs. Commercial DC's like the ones you listed have big fans to supply a huge airflow to overcome the SP losses in ductwork, maintain at least 4000 fpm on horizontal runs and still have plenty of airflow left at the tool for collection. Yes, they have to overcome the SP losses of a cyclone as well, but that big motor is there primarily to overcome a long run of ducting. IF you intend to install ductwork in your shop then you have no other choice than to spend $$$ on one of these, but if you limit yourself to hoses with short connections you can live with a DC-3300 or even a good quality ShopVac w/mini cyclone. Once you start contemplating a larger DC, it does become difficult to find a reasonably priced one with both a HEPA filter and cyclone because they assume you are hooking it up to ductwork so you get a 2HP whether you want/need it or not. I really haven't found a good mid-level DC w/cyclone in my past research. By the time you step up to 1.5HP or greater it puts you into the >$2k DC category. It would be nice if there were more options in that mid-level range for those of us who intend to run hoses and/or just a short section of ducting in our small shops. I haven't come across many good options here, but if you know of any please share them.

By the way, the Laguna and JET DC's that you show are what are known as "short stack" cyclones. You can tell by the short height cone and rather large opening into the dust bucket at the bottom. The benefit of these is they are shorter and can easily fit in low ceiling height shops, but the disadvantage is that their HEPA filter clogs faster than any other cyclone because the collection efficiency of that cyclone is a lot less than similar sized, but taller cyclones that are full height. IF you buy one of these short-stack cyclones, then plan on changing HEPA filters more often.
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Re: woodshop nerdery youtube channel

Post by Chad »

Wow Thomas, this topic sure did stir the pot.
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