Last edited by Alan Schaffter; 03-11-2016 at 11:23 PM.
If it could really pull 100" (or even 50") of SP, it might be really impressive. But consider that it pulls something like 23", max, and a "regular" DC will pull, what, ~13"? Compared to what you really need - a shop vac that pulls 120" - the "smart" technology is less than 10% "improvement".
I have a 5HP Smart collector. Others have explained how it works. Here is some data on my shop. I measured the airflow before when I was using a 2HP Super dust gorilla and with the 5HP Smart. I have a paper I wrote about dust collection but the short summary is:
1) Makers sell on CFM because it's easy to market.
2) Ports on machines are almost always too small.
3) The smallest diameter primarily determines the CFM.
4) For a given port size, the only way to pull more air is with more pressure at the port.
Here is the actual test measurement.
Shop Dust Collector Performance Super Dust Smart Measurement 2HP 5HP 2HP 5HP Effective CFM Ports Location Ft / Min Ft / Min CFM CFM Port size Increase Drum Sander 6" Inlet Dual 4" ports 3,000 5,750 589 1,128 6.0 192% Planer 6" inlet 6" port 3,460 6,770 679 1,329 6.0 196% Shaper 5" Upper Upper Hose 1,800 4,000 245 545 5.0 222% 3" Lower Lower Hose 1,800 3,900 88 191 3.0 217% Radial Arm Saw 5" port rear Center Back 2,420 4,550 330 620 5.0 188% 3" port to guard Front of Blade 148 550 2 7 1.5 372% Guard Elbow 910 1,780 20 39 2.0 196% 3" Flex hose 1,700 4,580 83 225 3.0 269% Bandsaw 5" port bottom Bottom 2,490 4,450 339 606 5.0 179% Behind Blade 566 725 77 99 5.0 128% Jointer 6" port bottom Top of Cutter 185 542 36 106 6.0 293% Flex hose 2,460 5,280 483 1,036 6.0 215% Table Saw 3.5" port below Guard Center 788 2,000 39 98 3.0 254% 3" port above Blade shroud input 1,450 3,325 126 290 4.0 229% Blade Cover Center 265 1,000 9 34 2.5 377%
I think it is an error to discuss any dust system in terms of 2.5" ports. For those a vac works best. A radial impeller with some speed control still needs larger gates to justify their benefits. I run machines from small 8" jointers with a 4" port to 16" jointers, 24" planers, and big shapers, many old iron. Runs are up to 50' long and have 25 gates. The impeller and filters are remote from the cyclone so there is resistance on both sides of the blower. A curved impeller, even at 17" diameter would not pull the cfm through an 8" reduced to a 7" pipe located 50 ft away to handle my old large machines to my satisfaction. A 15.75" radial not only gave me more cfm in that scenario but pulls 800+ cfm through a 4" port. The cost is that cfm per amp is lower so a 7.5 hp motor is needed. My shaper now gets 2200 cfm at 60 hz and I vary the speed from 55-65 hz depending on what I need. Not an answer for everyone, but there are times when a typical curved blade system won't handle a wide range of machine sizes. Dave
Remember, for most large woodworking machines CFM is the important part- it hopefully captures the dust in and around where it is generated and hopefully keeps it from wafting into the air- for that you need high CFM. For little stuff with little ports, the only way to go is with high SP, and hope for the best. Two totally different applications and physics.
Alan....perhaps you are correct. Do you have actual stats that compare a 3 hp cyclone to the 3 hp Smart cyclone. You are suggesting that there is very little difference. You also suggested that a shop vac will be much better. It would be most interesting if you have the data. Based on your comments you must have some actual data.
Have actual data on what you are suggesting would be very helpful as I consider the options.
We are still kind of missing the point here. To compare joe's smart to a normal 5 hp bc impeller system you would also have to use the same pipe and machines to get numbers that would mean anything. If Joe ran 8" or 7" mains to his big machines, a normal 5 hp would outperform his smart. With his 6" mains, the smart is likely to outperform due, not to the speed control, but to the type of impeller used. You can not assume that any system will perform a certain way compared to another unless you know the cumulative static pressure range you are likely to operate in. You can compute it somewhat, but it is very difficult to know the real numbers because you don't know the pressure drop of the filters, cyclone, or machine hoods ( all of which change with velocity ). The smart works best when you need to upgrade and have piping all ready in place that might be a little undersized or have a similar situation where full open cfm is less important than maximizing velocity on smaller ports ( 2.5" excluded ). Dave
Alan, David, and Dan are spot on with their assessment. Joe's numbers also tend to support their view.
A radial blade impeller (or any centrifugal fan) has a performance curve. The lower the system resistance (static pressure) the more air (CFM) it will draw at a given fan speed (RPM). If the system resistance is higher, the CFM will be lower at the same fan speed. The way to overcome this is to speed up the fan (shift the curve up) so that you generate more CFM and static pressure. The max speed is limited by motor FLA and maximum safe speed of the fan (may not be able to run it at 3600 RPM)
It is CFM that does the work of getting dust entrained and directed into the hood where it can be conveyed to the collector. The amount of SP required depends on the system losses. Since no two shop systems are the same, a canned product with given blower and fan speed will provide different CFM when connected to each of our systems. The Smart collector gives you some adjustability via the variable speed. However, the amount of extra SP needed for 2.5" ports versus the amount needed to overcome extra length of larger duct and a few elbows is significantly greater.
The other aspect no one has mentioned here is duct velocity. If your small ports are at the end of your larger system, you may have enough velocity in the small ports, but once it hits the larger mains, their is not enough velocity to keep the dust entrained in the larger ductwork.
I would think the Smart collector's benefit is being able to maximize airflow by maximizing FLA of the blower motor so you can overcome your specific system resistance by speeding up the fan to get a few extra inches of SP. It could also be beneficial for cleaning the area around the collector with standard 2.5" vac attachments, but you would want to connect this directly at the collector which is what I think Oneida shows (or at least used to). Sounds like it is quite an expense for these benefits, but it may be worth it depending on your perceived value.
If you look at the fan curves, though, you see what I said earlier: the Smart makes 23" max, a standard DC probably makes 13", a cheap shop vac can reach 80", and a nicer shop vac can make 130".
If you're looking for fine dust collection, you'll want to maximize CFM at low SP, so a regular DC serves you best (I suppose the Smart could serve you just as well, but it comes at a higher cost)
If you must use a small port (for a DA sander, router, etc), you want max velocity, so you want max SP. Seems like an obvious candidate for the 120" SP capabilities of a shop vac.
Where is the situation where you want max CFM and only a minor increase in SP capabilities through small ports? It's probably what Mike says - you've got duct already installed, more money than time, and just want something that will sorta work.
A couple of points concerning what I am trying to do---
- My current dust collector is a 1.5 hp Jet Vortex and is not sufficient for my needs and will be buying a cyclone dust collector.
- I currently have 4" PVC and intend to put in 6" PVC.
- I have looked at shop vac and they are noisy compared to a dust collector not in the shop.
- I want to use the dust collection at times when I am hand sanding on a small down draft table so the noise is an issue for me.
- If I used a shop vac it would have to be HEPA rated.
- I would like to avoid having another thing like a shop vac sitting around in my shop.
- Performance data for HEPA rated vacs is not very easy to find.
- By the time I spend $300-500 for a HEPA rated vac, I could use it to fund the difference between a standard a nd smart cyclone. A Ridgid HEPA shop vac is $349and is rated at 105 cfm.
It is somewhat difficult to compare prices and performance data with various cyclones. I have had to be careful to make certain that they all include the same things such as a stand, bin level indicator, dust bin, etc.
Also, the way performance data is presented is really inconsistent. I was a bit disappointed with ClearVue as they provide very little data on the website.
I appreciate all the comments made as they help me figure out what I will do.
All published data on dust collectors is tough to compare. If you are looking at the 3 hp smart vs the clearvue and have the amps available, you should give the CV max a look. The larger 16" impeller will pull more through a 6" main than either the CV or Oneida 15" 5 hp system and will likely come close or exceed ( I'd bet on exceed but no data ) the 3 hp Smart when restricted. The 5 hp Smart might have better high pressure cfm than the CV max but I doubt the smaller smart will. I understand the potential benefit of the larger smart collector but not the smaller one. I've run a smaller 15" radial with a 5 hp motor before I upgraded and would not spend a lot for speed control with a smaller one. The benefit of speed control and a radial impeller is to oversize and throttle down, not to run at full with a smaller size. Dave
My vac cabinet is vented for air flow and cooling. It doesn't overheat, just gets acceptably warm ("At the end of 90 minutes of continuous vac operation the temperature in the cabinet had only increased to 94.5º F - not quite normal body temperature!"). (American Woodworker was concerened so had me test it before they published my article)