Any advantage to a larger cyclone?

[Aaron Montgomery]

As my shop is being reincarnated again, I'm wanting to get a cyclone to replace my HF DC when I put it back together. I've certainly got some ceiling height issues with a maximum of 91.5", but my question revolves around airflow of various cyclones. I plan to reuse the 6" S&D ductwork I took down for the remodel. So my question is this. What if any advantage is there to using a larger DC with 6" ductwork.

An Oneida V3000 has a 6" inlet rated at 1285 CFM @ 3" SP w/ Filter
An Oneida V5000 has a 8" inlet rated at 1,498 CFM @ 1.65" SP
An Oneida 3HP Super Dust Gorilla has a 8" inlet rated at 1554 CFM @ 1.8 SP w/ Filter
A Grizzly 441 has a 8" inlet rated at 1654 CFM @ 2.0" SP

I have to believe that choking the 8" inlets down to 6" will reduce their rated CFM to the point that it would be competitive with the V3000. I could believe that it would be at a higher static pressure though. I can think of a couple of disadvantage, in the way of price, size and noise. So what, if any advantage is there to going with a larger DC and 6" ductwork?

[Jeff Monson]

Thats a great question, I'm no DC expert but the only advantage I could see would be the larger cyclones will have more cfm on longer runs of duct, and would also be able to handle multiple machine operation at one time better.

[Aaron Montgomery]

Thanks for the reply Jeff. I would expect that as well. I did get to thinking though, that maybe a DC rated at a higher CFM might still move that volume of air in smaller ductwork with a higher airspeed. Just conjecture, but I was hoping that the knowledgeable folks on this board might be able to definitively state that there are tangible benefits to using a higher rated cyclone with ductwork smaller than the cyclone inlet.

[Rod Sheridan]

Hi Aaron, the first step is to draw out your shop with present and future needs identified.

Then you can design the ductwork, which will allow you to calculate the airflow and static pressure requirements.

Once you have those two numbers, you look at the airflow/static pressure curve for the cyclones you are considering and see if they will work. (I believe the Bill Penz site has an easy to use static pressure calculator, just remember not to include filters, cyclone etc in the calculations as that will be taken into account by the fan curve you get from the manufacturer).

The two numbers you provided are almost useless for determing cyclone performance.

regards, Rod.

[glenn bradley]

This will become a long and painful discussion but, an important one. I have a G0440 2HP unit. I would not want any less and would certainly enjoy more if I could get it to fit. Knowing now what I thought I knew then, I would have rearranged the shop to make the larger unit fit as my needs have only increased, not decreased. If I had the larger unit and needed better performance I could change ducting cheaper than I can forklift the whole thing.

[Paul Wunder]

Aaron,

Have you considered a ClearVue cyclone. It is rated for more cfm at at higher static pressure levels than the units you mentioned, but more importantly, it does it while using a 6" inlet. Further, even though ClearVue states that 96" is required, I only had 91" (from the floor to the top of the space in between my joists in the basement). I simply mounted the motor, blower, etc. to a bracket between the joists and used a 35 gallon fiber drum from Penn State Industries. Ed Morgano, from ClearVue sent me some blueprints showing me how to make a simple joist bracket. If you go that route, I will be happy to send the specs to you.

Paul

[Philip Rodriquez]

Aaron,

I suggest calling Oneida and have them size the machine. I was ready to buy anything and they suggested the V-3000. All of my runs are short and I cannot get my wife to help me in the shop. Therefore, I only run one machine at a time. I even have more than enough to run my TS and Excalibur overarm BG.

With 5 drops, it only ran me $2,200... I would have spent twice that and they knew it! They are great!

[Aaron Montgomery]

Thanks for the responses. I was planning to call Oneida and talk with them, but I wanted to be a little more knowledgeable before I did so. I expect the drywallers to finish up next week and the height limit will be around 91.5" as the ceiling will now have finished drywall on it. (previously open) I'll probably try to arrange my tools so that I have a better idea of the layout before I give them a call. I am planning to move things around a bit from the previous setup. At this time, I'm planning to reuse my existing 6" S&D, but I'll see how much Oneida quotes me for metal ducting. I'd much prefer to go that route, but like everything else, it will depend on the cost. I'll post back after I've talked with Oneida and made a decision.

[Philip Rodriquez]

Aaron, I think you are on the right track. Work out where you want everything and send them a detailed drawing of your shop, including port size and locations. Be sure to let them know how many machines you'll be running at the same time - this is a huge factor.

Have fun with it!

[Jim Becker]

Aaron, when I installed my current Oneida system, I accommodated its 7" inlet with 7" duct work for about the first 6 feet...out to the first branch. It then transitioned to 6" which was already in place/reworked from the previous smaller cyclone system. I agree with your intention to call and speak with Oneida about this, however. I see no need to totally rework your duct work, assuming it an efficient design, but you may want to make some adjustments like I did.

[Jeffrey Makiel]

I think 6" duct is plenty for the home shop. By home shop, I mean a shop about the size of a 2 car garage maximum and no giant stationary belt sanders, and only one machine runs at a time.

If you decide to put a larger cyclone (like a 3 hp one with an 8" inlet) and use 6" duct, it should not hurt the motor on the dust collector as most manufactures either use radial or backward inclined wheels. In fact, these blower wheels are generally designed to draw less current at lower flow (i.e., when being choked off). However, I don't know if the lower flow will hurt the cyclonic separation. That is, the design radius of the cyclone is most effective within a certain cfm range.

Anyway, the 3 hp cyclone will pull more air thru a 6" duct as common sense dictates, but since pressure loss is the square of velocity (or flow), and the cube of power, the law of diminishing returns kicks in. That is, at 50% with more power and a larger wheel, the flow may increase 12% at most.

Other considerations are:

• Is it likely that you'll greatly increase the size of your shop in the future, or perhaps buy some large commercial equipment?
• Is noise going to be an issue with you?
• Do you have the room, especially head room?
• What is the quantity and size of ports on each machine? Is there anything that requires more that one 6" drop or two 4" drops?
• Do you have the electrical service? 3hp may require 30A service.

cheers, Jeff

[Aaron Montgomery]

Thanks for the reply Jeff.

I'd love to have a larger shop in a large outbuilding, but it's not possible at the current residence and it looks like I won't be moving for the foreseeable future. Even if I do move, I don't see my equipment list changing. The basement shop ceiling is now drywalled and any DC solution will have to fit within the 91.5" height.

I am a one man hobby shop - one machine at a time. The only future equipment that I am planning for is a ~12" jointer and possibly a 25" drum sander. If I can someday afford that large wide belt sander, I'll probably be able to afford the new cyclone required of it as well.

Noise is a concern, it's what drove the remodel. It's what also has me eying the V3000 based on posted db ratings.

All machines that can be converted to 6", have been.

Power isn't a problem unless we get beyond 5HP or attempt 3 phase.

I'm still a few weeks out from contact Oneida and making a decision, but I'll post back when I do.

Aaron

[Mike Archambeau]

I am running the V3000 and it is amzing how well it works. Oneida can help you make the right choice. You should tell them what machines you are running and how spread out they are. They can do this on the phone. If you buy a #hp or higher they have free design service.

[Alan Schaffter]

Rod and Jeff pretty much nailed it. Though not the same in engineering terms I liken the power issue to sailboats- put a 25 hp motor on one and you can do a nice 8-10 mph, put a 50 hp motor on it and you might see maybe 12 mph.

Also, look closely at the fan curves. As you noted the 3000 and 5000 appear to be VERY similar. If you choke down that 8" inlet you decrease the CFM and also increase the SP- so without seeing the fan curve, they appear to have the same blower.

Remember, with DC's bigger is always better. Excess capacity is never a bad thing.