Comparing cyclones - need help

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ShawnB

Guest
I'm about to take the plunge and set up a formal (hobby) shop, primarily for my lathe but also to include collection from infrequently used tablesaw, drill press, etc. I've been comparing cyclone performances...I know, that is difficult at best. What I need some help with is the CFM readings because one comparison has me very surprised. The performance curve for the ClearVue system shows ~1800 CFM at a static pressure of ~8. Looking at a new cyclone by Oneida (Dust Gorilla) I see ~1400 CFM at static pressure of 1 but that drops to below 500 by a static pressure of ~8. Most of the commercially made cyclones in this class/size also show these types of performance curves. I'm just trying to understand what is so drastically different - have a hard time believing the design of the Oneida (for example) is so inferior. What's the deal(?) and is this performance difference actually important for a small shop of ~15'X20' using only one machine at a time? (disclaimer: no affiliations with any company....just confused and dusty)
 
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imported_admin

Guest
Shawn,
First, our unit is a 5hp system and the oneida Gorilla is a 3hp unit. With only a 10' long 6" pipe attached to our blower, the motor draws 18 amps. Attached to the cyclone and with a 6" gate open close to the cyclone our motor draws 16 amps. That means that it is doing more work than a 3hp motor is capable of. So we are selling a 5hp system for less that you can buy the other 3hp systems for.

Second, because I didn't have the gages necessary to perform the tests here, I sent the impeller to Bill Pentz to do the test. Because of his health Bill did the test on the Blower only - without the cyclone attached. That will explain part of the difference, but I do beleive that we have a superior product. We have done a lot of tweeking if you will to try to increase performance. Bill finally sent me some gages and I did some of my first tests today, so I'm kinda glad you asked today and not yesterday. Right out of the blower with nothing attached and all closed, I got a reading of 16" of static pressure. That's a very good suction. On my system that I just recently installed, I measured the air flow thru a 4" pipe that was connected to a 6" line that had 3 90 deg els in it and was about 10' from the cyclone. I measured 789 CFM thru the 4" pipe at 5" of static pressure. This test was done only with a 4" pipe....not the way we usually measure it, so the static reading is low (only measured in the 4" pipe) instead of restricting a 6 or 8 pipe which will increase the static pressure in the pipe. Anyway, oneida measured 700 cfm thru a 4" pipe and Grizzly claims a higher number. Those are on their 3hp units. If you have looked at the others, you will find that they have 2hp systems with 12" impellers and 2hp systems with 14" impellers and yet 3hp systems with 14" impellers and 3hp systems with 15" impellers. Impeller design has everything to do with blower performance. Some of the blowers are quieter than ours, but don't move nearly as much air.

As to whether you need that much, that just depends on how much dust you want in your shop. The other thing to think abouit is do you want to have to buy another system later when your shop gets bigger. Personally, my shop has never been so clean since I put in the new system a month ago. P.S. We have a gallery at http://www.gallery.clearvuecyclones.com if you want to look at some pictures.

Ed
 
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ShawnB

Guest
Thanks Ed. That helps explain things alot; the performances are much closer than I originally could decipher from comparing performance curves. For example, the Gorilla drops below 800 CFM at ~6.5 static pressure. From what you describe in your tests today that may be right in line with what you measured (considering your comments on static pressure being a bit above 5 in your tests - I think I'm understanding that right(?)) BTW, the Oneida Gorilla is actually a 2hp unit with 13.5" impeller. Of course there are others out there too - like the Grizzly. And I have confidence that yours is a great product. Ah, decisions. Thanks again.
 
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