Another DC Question

[Jim Chilenski]

I have been reading the messages on dust collectors on this site but haven't been able to find an answer to my question, so here it goes.

I have a Delta Model 50-181 Two-Stage dust collector. This unit was built for Delta by Cincinnati Fan and is sold by them as their model 200S. It has the following specs.

Motor HP 2
Max CFM 1100 (Maximun CFM at 0" SP with 5 feet of 6" hose)
Max SP 8 1/2" (Maximun SP at which no air flow)
Fan Dia 12 1/4"
AMPS 230V 5.6
Filter Bag 18 SqFt 5 micron

All of my 24 feet of duct work is 6" in diameter and I use short sections of 6" flex hose to connect to each machine. Currently when I use the system a lot of particles end up it the filter bag. This may be happening because I do not have the fiber drum for this system and use a rubbermaid barrel instead. The fiber drum would have sides that are straight up and down where as the Rubbermaid barrel's sides taper in at the bottom. This may be contributing to the large particles being sucked through the fan and into the filter bag. I would like to add a cyclone in front of this unit to try and remove more of the fine dust particles and chips before they get to the filter.

Now my question. Does this unit, from the specs above, have enough umph to be used with a cyclone like the clear view? Or using Bill Pentz's specs could a cyclone be built that would work? What throws me is the 1100 CFM with 5' of 6" hose. This seems to be above the CFM of the units tested in FWW.

Thanks,
Jim

[Jim Becker]

If you are getting blow-by on a two stage system, that's a sign of an air leak between the bottom of the separator and the bin.

[Jim Chilenski]

Jim, you've lost me there. This is a two stage system where the blower unit and the input and output are part of the lid which sits on top of the barrel or drum. Since I have weather stripping around the edge of the lid sealing it to the barrel, and there isn't a crack in either the lid or the barrel, I don't know where there could be an air leak.

Here is a link to a picture of the unit.

http://www.cincinnatifan.com/DustCollector.html

In this picture they show the unit on a 55 gallon drum which only has a diameter of 22 inches. That is why I use a Rubbermaid barrel because it has a diameter of 24 inches and fits tightly, with the weather stripping, to the lid.

Thanks,
Jim

[Mac McAtee]

Without a cyclone you are going to get materal that by passes the barrel. A cyclone is much more efficent at separating the wheat from the chafe. Build a cyclone, not hard to do.

[Jim Chilenski]

Mac, I agree. But is my blower powerful enough to use with a cyclone? And if it is, will it work with the Clearvue, or can I build one that would be efficient with this blower? I really would like to avoid buying another blower to use a cyclone. I could just live with having to empty the filter bag every other week.

Thanks,
Jim

[Steven Wilson]

It would be much better if the fan diameter was 14" or above, 12 1/2" is a bit small. You could try the small cyclone from Oneida, they use to make one for retrofit installations. Give them a call and see what kind of numbers it would make with your system.

[Bill Pentz]

Jim,

My apologies for the dissention in the prior posts, but Ken as moderator did an excellent job helping with this ongoing problem. I just wish Ken had not been forced to step in.

I do know a bit about your dust collector as I owned an exact twin. Cincinnati Fan made these in a range of sizes from 1/3 hp to 5 hp models (check out http://www.cincinnatifan.com/pdfs/PMD1203.pdf for exact specifications), plus for various customers they also made these with aluminum blowers and impellers. Delta, RBI, and a few other firms also sold these same units under their own brand names. Although a few copies such as the Granger used Dayton blowers, most were configured with Cincinnati blowers and customer supplied motors. My 200S used the Cincinnati Fan aluminum blower housing and aluminum impeller wheel, but most used the Cincinnati steel blower housing and impeller. The steel is tougher than the aluminum housings and impellers, but not quite as efficient at moving air, plus has a higher startup load because of the extra weight. A few vendors still sell these identical units, but commercial prices tend to be high in the $800 plus range for your 2 hp sized unit. They perform so well that even used and surplus units of this size command $400 plus sale prices.

This unit was engineered well before the 1989 OSHA fine dust collection requirement for large woodworking facilities went into place. In other words, it was engineered to be and remains an excellent “chip collector”. That means it does a great job of picking up the sawdust and chips that we would otherwise sweep up with a broom. It also predated and probably helped to spawn the trashcan separator lids. These work well with lower airflows but not so well with the larger ducting and airflows. I know on my unit when I choked it down with the supplied reducer to use of 4” pipe it was a champ and put almost all the sawdust and chips into the bin with nothing but fine dust going into the filter. When I shifted to a 6” hose directly connected to a tool with hoods that supported good airflow, that additional air movement scoured my dust bin empty filling my filter with all but larger sticks and blocks.

I played with my unit quite a bit adding a 90 degree elbow inside that forced the air to cycle around the outside of the bin. That made a big difference, but just not enough as the filter still kept filling. I also changed out the filter to a much finer oversized American Fabric Filter (AFF) fine bag. That made a big difference in total airflow. The finer strands in that filter provide better filtering, but also put so much less surface area in the way of the airflow they move the air with less than half of the resistance. Below is a picture from my web pages to try and help. A taller straighter barrel also helped.

http://billpentz.com/woodworking/cyclone/FilterDensity.gif

I tried powering my cyclone with an 18” diameter with my blower in a pull through configuration. Although it worked, there was a problem in the extra resistance added by the cyclone having to work so hard to turn the air in its tight separation spiral that it really degraded the airflow. I was getting a real 1000+ CFM with the 6” before adding the cyclone and after did not even get 800 CFM.

The good news is when I did this work was early on in my cyclone adventures, so I now know a little more about how to make repair. If you can find one of the 13” impellers it will fit in that same blower housing and give you extra pressure to overcome some of the high resistance of your cyclone. Likewise, instead of making my standard 18” cyclone design, use a 22" cyclone that sacrifices a little separation efficiency in trade for reduced resistance. Although you can buy inexpensive cyclones that would work fairly well if you can blow the dusty air away outside, if you plan on filtering then I would suggest making or buying my cyclone design. Larger diameter cyclones have lower resistance because they do not need to turn the air in as tight of a spiral. So with that bigger diameter cyclone and upgraded impeller that blower will give you over 800 CFM with ample pressure to wheel the unit between machines.

Because the bigger diameter makes for a taller cyclone, most end up needing to mount the blower apart from the cyclone instead of on top. I know of a few who have modified standard dust collector filter trees to hold a cyclone with bin below, then power that unit with the blower to the side creating a cyclone system that rolls around like a portable dust collector. The easiest way to power the cyclone without the blower on top in a pull through configuration is to make it a push through with the blower blowing into the cyclone. I prefer to protect my blower impellers from the material hits with a pull through configuration. I show some ways to pull the air from the cyclone side instead of the top on my pages.

With all this said, do I think it is a good idea? The answer is a firm reluctant maybe because it depends upon if you can get that larger impeller at a good price and are willing to live with lower separation and minimal ducting. I personally finally gave up on mine and built my own cyclone. These are great units that are in fairly high demand. I sold mine for nearly enough to cover the cost of my cyclone and blower parts including motor but not filters.

Edited to clarify the specifications for this unit and explain it can be used for either pull through or push through configurations.

[Jim Chilenski]

Bill,

Thank you for taking the time to reply to my question. I have admired your work and dedication to the hobby wood working community since I first discovered your web pages two years ago. Thank you also for clearing up one thing that has been confusing me for sometime. That the larger the diameter of a cyclone, the less airflow needed for good separation. Because of the appearence of the 'shop vac' cyclones that are smaller in diameter, I assumed that a smaller cyclone would require less airflow, not more. This is why I was interested in the ClearVue cyclone and hoping to be able to use it as a pull thru type. You have cleared that up for me.

Would it be possible to build a 24" diameter cyclone, especially since my two stage unit has a 24" diameter lid, that would also be as effective as the 22" unit you describe on your web page?

I too have added the elbow from Cincinnati fan inside the unit to try and improve the separation, with the same poor results. You have also confirmed that my use of a tapered wall barrel may be contributing some to my problem. I may try to find a 65 gallon fiber drum which has a 24" diameter with straight sides, and maybe even try connecting two of them together one on top of the other to see if that improves the separation.

My hope is that I could get the separation good enough that I would then feel comfortable replacing the 5 micron bag with a cartridge filter that would increase the amount of surface area allowing for better air flow while providing filtration down to 1 micron. I need to filter my air because I can't afford to pump 1000 CFM of heat outside during the Ohio winters.

If not then my best possible solution, while keeping the same blower unit, would be to build your 22" cyclone and use my blower for a pull thru system.

When you were working with your Cincinnati Fan unit did you ever try their 3hp filter bag which attaches to a garbage can and is hung from a ceiling mount? Even though its only 5 micron filtration I was interested in it because of the sheer amount of surface area it offered.

Thanks again!
Jim

[Alan DuBoff]

Pardon my ignorance on this subject, but the one thing I haven't seen discussed recently is if one was content to use a single stage canister type DC, could build one themself with a 3HP or 5HP motor and create tremendous suction? Seems that most products change to a 2 stage when they get to 3HP.

I think I would be ok to hook a hose to each machine, to be able to have a simpler solution, rather than dwelling on a cyclone. Although, a cyclone with a direct hose might be a good solution, that would have to suck! :eek: I could always add ducting in later.

Is there something wrong with that concept, or is a cyclone not good for that purpose, connected directly to the tool?

[Jim Becker]

Jim, you've lost me there. This is a two stage system where the blower unit and the input and output are part of the lid which sits on top of the barrel or drum. Since I have weather stripping around the edge of the lid sealing it to the barrel, and there isn't a crack in either the lid or the barrel, I don't know where there could be an air leak.
Sorry...I was in a hurry and didn't take the time to look up the unit. I do recall that others with similar units have sometimes posted about blow-by. Don't assume that weather stripping is giving you a seal...this is one reason that most commercial cyclone setups have a lid on the bin that clamps on.

I don't know much about your system, but see that Bill has posted some good experiential information on it.

[Bob Dodge]

I have been reading the messages on dust collectors on this site but haven't been able to find an answer to my question, so here it goes.

I have a Delta Model 50-181 Two-Stage dust collector. This unit was built for Delta by Cincinnati Fan and is sold by them as their model 200S. It has the following specs.

Motor HP 2
Max CFM 1100 (Maximun CFM at 0" SP with 5 feet of 6" hose)
Max SP 8 1/2" (Maximun SP at which no air flow)
Fan Dia 12 1/4"
AMPS 230V 5.6
Filter Bag 18 SqFt 5 micron

All of my 24 feet of duct work is 6" in diameter and I use short sections of 6" flex hose to connect to each machine. Currently when I use the system a lot of particles end up it the filter bag. This may be happening because I do not have the fiber drum for this system and use a rubbermaid barrel instead. The fiber drum would have sides that are straight up and down where as the Rubbermaid barrel's sides taper in at the bottom. This may be contributing to the large particles being sucked through the fan and into the filter bag. I would like to add a cyclone in front of this unit to try and remove more of the fine dust particles and chips before they get to the filter.

Now my question. Does this unit, from the specs above, have enough umph to be used with a cyclone like the clear view? Or using Bill Pentz's specs could a cyclone be built that would work? What throws me is the 1100 CFM with 5' of 6" hose. This seems to be above the CFM of the units tested in FWW.

Thanks,
Jim

Jim,

You're talking about the now discontinued 2 stage dc's made for Delta, and Dust-Boy. Dayton blower if I remember correctly. With that 12 1/4" impeller, you should have plenty of suction for 6" drops, if they're properly balanced and designed. You would not want to use a blower like this, in a standard pull-through mode, like you see on most cyclones. Use it in Push-through mode, and you'll be ok. In otherwords, you'd connect a short exhaust duct, to your cyclone inlet. What size outlet does your blower have?

Regarding hooking up your ducts, you'd dismount the blower from the drum you're now using, and connect the pipe directly to that blower's intake. I'd need a few more specifics regarding your inlet and outlet diameters.

Another option, would be to make a simple box-plenum, and sit that on a drum. Cut a hole in the top, to mount a filter, and cut a hole in the bottom, to feed waste into the drum. Exhaust your blower into the side of that plenum, and down into the drum.

Bob

[Jim Chilenski]

Jim, I understand. No one can know every unit on the market. If I can make this work I'll try to attach a picture of my system.

38234


The clear 4" hose hanging in front is not connected and is used to connect my planer to my duct work. The lid because it weighs around 80 pounds seals tightly against the weather stripping that I have on the top lip of the Rubbermaid barrel. There is also weather stripping on the inside of the vertical lip of the lid as well.

Thanks,
Jim

[Bob Dodge]

http://www.owwm.com/PhotoIndex/detail.asp?id=1710

Here's your dc. Look at the reduction they're using on the outlet. You'd want to get rid of that reduction.

Bob

PS. On your shop-built plenum, you could mount a cannister filter on top of the plenum. Your call.

[Jim Chilenski]

Bob,

Thanks for your suggestions. That link that you posted does indeed show my collector, but mine never did have the reducer that they are showing. Mine has a 6" inlet and a 6" exhaust directly into the filter bag. I've posted a picture of the collector in one of my responses, (don't want to repeat it and eat up space on this web server). If you look closely you can see the collector and my duct work in the following photo along with one of my home made blast gates. The 4" hose that is hanging in front of the drop ducts isn't connected to anything.

Thanks,
Jim

38235

[Bob Dodge]

Jim,

That blower, if you look closely, has a 5.6 amp motor, despite having a 12 1/4" impeller. It's probably designed as a low-resistance set-up. Yes, it will move a fair amount of air, but only if the resistance is not too high. Otherwise, you'd overload the motor.

You probably have plenty of suction if you just exhaust into that shop-built plenum I described. With a cartridge filter on top of that plenum, you'll reduce outlet resistance compared to your present small bag. You'll also get far better filtration.

You'll also reduce suction-side losses, because you'll not have your blower mounted on it's present drum. That drum gives you resistance, and you'd be better off using that resistance for your pipes.

Instead of having the blower sitting on that drum, just build an open stand, like a small table. Cut a hole slightly larger than the blower inlet, and sit your blower on that table. Connect a 6" pipe to the inlet, and run it down, under that table, and across to your saw's base.

At the saw-base, run a 4" take-off to the base, (6x4x4 wye) then run the other 4" branch to your overarm blade-cover.

I'm having trouble seeing details on your picture. It's a small pic, so if you will e-mail me a copy, I'll be able to see it better. Or maybe, send it to my "private messages". I could then perhaps "zoom" in.

Bob

[Bill Pentz]

Jim – Thank you for your kind words.

Would it be possible to build a 24" diameter cyclone, especially since my two stage unit has a 24" diameter lid, that would also be as effective as the 22" unit you describe on your web page?
Absolutely, and the 24” would be a better solution with this unit, but you are going to lose some fine dust separation efficiency. My measuring of a 22” diameter cyclone showed the find dust separation efficiency fell by nearly half. The 24” will be even worse which is why with the resale so high on one of these that I recommended using that equity to buy or build a more efficient cyclone.

When you were working with your Cincinnati Fan unit did you ever try their 3hp filter bag which attaches to a garbage can and is hung from a ceiling mount? Even though its only 5 micron filtration I was interested in it because of the sheer amount of surface area it offered.
No, I instead bought an oversized bag from AFF. It flowed more air, but also rapidly clogged because my unit just put too much dust into the filter.

Alan,

Pardon my ignorance on this subject, but the one thing I haven't seen discussed recently is if one was content to use a single stage canister type DC, could build one themselves with a 3HP or 5HP motor and create tremendous suction? Seems that most products change to a 2 stage when they get to 3HP.

Yes you can make an excellent blower to power a single stage blower for a very reasonable cost (<$200 if you scrounge a good used motor) using my Budget Blower plans. I know quite a few who have done just this and then blow their dust away outside into a big drum topped with a large open filter bag that freely passes most of the fine dust. Should they later choose to power a cyclone, they are already set with a good blower.

[Alan DuBoff]

Yes you can make an excellent single stage blower for a very reasonable cost (<$200 if you scrounge a good used motor) using my Budget Blower plans. I know quite a few who have done just this and then blow their dust away outside into a big drum topped with a large open filter bag that freely passes most of the fine dust. Should they later choose to power a cyclone, they are already set with a good blower.Yes, this is exactly what I was thinking, that if I did get a decent motor for that, I could easily use it for a cyclone in the future if I wanted.

What about building a cyclone, less the ducting, and connect it directly to the tools? Will that work reasonably also, or does the cyclone need more ducting? That would also allow for adding in ducting later to supplement the system.

[Bill Pentz]

Alan,

What about building a cyclone, less the ducting, and connect it directly to the tools? Will that work reasonably also, or does the cyclone need more ducting? That would also allow for adding in ducting later to supplement the system.

If you go with the 14” impeller, nice Leeson 5 hp motor, and cyclone with minimal ducting you will be fine. The 15” impeller needs the extra overhead of the ducting to ensure not pulling more than the 5 hp that motor can provide.

[Bill Pentz]

Bob,

Again your responses on this thread have irritated me from too many emailing about the accuracy of your information. I realize you really dislike anyone who questions your expertise, but please look over my following detailed responses to your commentary highlighted in red. Hopefully my taking the time to respond will help educate as to why I asked you to not use me or my site as your reference. Large amounts of information that is only partially correct, incomplete, or not carefully thought through causes confusion and problems in those you are trying to help. Please be more careful.

Overall, the only reason that I can see for your even bothering to respond to this thread was to give out lots of information to perhaps make others think you had lots of expertise and personal experience then use that perspective to challenge what I already said. I personally hate to respond to topics that you have responded to simply because doing so puts me in the awkward position of having to so often hold my tongue on not pointing out concerns. In this case I already responded not only from the vantage of being fairly well versed, but also as a long time owner and user of the specific unit in question. Based upon your comments, your familiarity appears to be limited to information off my pages, the vendor pages, and prior posts from other knowledgeable people.

That blower, if you look closely, has a 5.6 amp motor, despite having a 12 1/4" impeller.
This is true only for some of the units made directly by Cincinnati Fan. Many others bought just the blower and can top adding their own motors. Some like Grainger with their Dayton brand used their own blowers, can tops, and motors. Motors also changed among vendors during the twenty some years these units have been sold, so amperage ratings do vary. Each needs to check and verify both the amps and motor service factor on their particular unit.

It's probably designed as a low-resistance set-up.
This is a high resistance setup that pulls just about double the resistance of similar sized dust collectors. The dust bin arrangement on the one of these that I owned and used for more than ten years measured with “seasoned” filter and 55-gallon drum attached at 4.3” of resistance. This is more resistance than adding a cyclone with a set of good fine filters. This constant high resistance is why this good sized impeller can be powered with a relatively low amperage motor without risking burn up. Motors burn up when a big impeller sized for a high resistance gets used in a low-resistance setup. The motor simply tries to push more air than it has amps to support.

Yes, it will move a fair amount of air, but only if the resistance is not too high.
This unit is engineered to move a maximum of 966 CFM at 4” of static pressure drawing just over 2 hp. Changing over to the 4” pipe adapter that came with mine and using 4” ducting to a nearby machine brought the airflow down to about 670 CFM on my unit with a measured static pressure of about 8”. Use of 6" ducting, hoods, ports, flex could easily add the same static pressure overhead that kills performance. Adding the roughly 2.32” of resistance for the ducting and hoods for a typical two port larger tool, this unit still moved the roughly 800 CFM needed to meet what air engineers recommend as the minimum to provide OSHA level fine dust collection on our larger tools. Adding the 1.69” for a typical longest run in a 1-car garage sized shop dropped that CFM to only 662 CFM at 8”. These with the real Cincinnati Fan blowers, not the lower performing Grainger Dayton blowers, run one of the absolute best performing industrial blowers. My testing found these Cincinnati Fan blowers consistently perform better than almost all small shop units with only the Jet and Delta dust collector blowers coming close. This again shows why a 2 hp that is an excellent chip collector is too light to be used for good fine dust collection with anything less than a minimum of ducting.

Otherwise, you'd overload the motor.
Although you mean well, you were not clear that this motor was equipped with a vendor intentionally oversized impeller to meet an already known high resistance. In this case anything a person does to reduce that resistance below about 4” puts the motor at risk of trying to move too much air causing it to overheat and burn out. Just putting on a higher airflow fine filter can put this unit at risk if you reduce the resistance below 4.1”.

You probably have plenty of suction if you just exhaust into that shop-built plenum I described. With a cartridge filter on top of that plenum, you'll reduce outlet resistance compared to your present small bag. You'll also get far better filtration.
Bob you previously failed to point out that this motor is at risk when used with under 4.1” of resistance. You then followed up providing what you say is an expert opinion that the owner of this unit should make a rectangular plenum topped with a large fine cartridge filter. You introduced some confusion by using the word plenum without a definition, then instead of using that as a true plenum meaning take off point for ducting, you use it in place of saying drop box. Your recommended large cartridge filter and this plenum will immediately drop the filter resistance by up to 3" pushing the motor to draw over its rated 2 hp. This is not a very good suggestion in terms of motor life unless you also caution that you are going to make up the needed resistance to safely run this sized impeller with ducting overhead. Again an amp meter would be a must here. With less amps than its factory setup then it has more resistance and less airflow. More amps indicate better airflow. Amps over the motor’s service factor times its amp rating means a sooner burned up motor.

Additionally, I found from my own testing and experience that plenums without a separation screen simply eat fine cartridge filters ruining them in short order. They put too much filter destroying fine dust into the cartridges, plus pack the filter pleats full of too many chips unless the plenum is made drop box sized or equipped with a separation screen. Moreover, you also forgot to mention that building this plenum in wood creates a potential fire hazard worsened by building with rectangular corners that create dust piles which also pose a fire hazard. Worse, when the airflow is restored the piles that build up in the square corners at lower airflow slam sharp chips around that ruin fine filters by poking them full of holes.

You'll also reduce suction-side losses, because you'll not have your blower mounted on it's present drum. That drum gives you resistance, and you'd be better off using that resistance for your pipes.
Trying to answer every dust collection question on every major woodworking forum is a serious challenge that often leads to little errors such as use of it’s in place of the possessive form denoting ownership for the indefinite pronoun. The error is trivial, but important because it is indicative of similar but more important errors in your responses. For example think about what you said here. You introduced suction-side losses without explaining that suction side means all resistance on the intake side of the blower such as ducting, hoods, ports, and cyclones. That also needs covered with outlet side losses meaning the overhead for our ducting, filters, etc. You then should tie those pieces together explaining that adding up all these resistances for our biggest overhead demand machine and longest run lets us size our dust collection blower so we can move any tool anywhere we want in our shops and still provide ample airflow without needing a bigger blower. Otherwise, we end up having to mostly keep our dust collection blower right next to our larger high demand tools. You also made a second far more important point that got lost in your words. What I gathered from my vantage is you believe separators don’t work well and kill the airflow when used with smaller blowers. After finding this point, I don’t agree with you, particularly for folks only interested in chip collection. A separator works wonders and saves a lot of trouble in emptying typical dust collectors. Likewise, if you don't work with toxic woods, a good dust collector that moves ample air is an excellent fine dust collection solution if you blow the fine dust away outside using a separator to keep from spraying chips and sawdust all over. You do need to do a little work to match the right size and type of separator to your airflow.

Instead of having the blower sitting on that drum, just build an open stand, like a small table. Cut a hole slightly larger than the blower inlet, and sit your blower on that table. Connect a 6" pipe to the inlet, and run it down, under that table, and across to your saw's base.

At the saw-base, run a 4" take-off to the base, (6x4x4 wye) then run the other 4" branch to your overarm blade-cover.
Depending upon the series and vintage of this dust collector the blower opening can be up to 10”, so that opening was actually set and controlled by the can top having a 6” opening. Adding a 1’ long tube to that can top opening that projected into the dust bin was the biggest positive benefit I had on my unit, but did require emptying the unit more often. My Cincinnati Fan blower on my unit opened to a full 7” when not bolted to that can lid. With a 7” opening this sized impeller generates more than 2 hp until over 7” of resistance. You should have said size the wooden hole at 6” to keep from potentially burning up your motor.

Additionally, with this motor blower combination hard pressed to move the 792 CFM required to meet the somewhat remiss OSHA fine dust collection standards for a table saw, giving away 12% of your airflow because you used two 4” pipes is also not a good idea. These two pipes constrict your airflow by a needless 12%. You should go with a 5” below and 3.5” above. The 3.5” pipe can be purchased from Wynn Environmental.

I know this may all seem picky and awkward, but the concern is very real. You should not give out advice that will burn up motors, ruin filters, and put woodworkers at higher risk of fine dust exposure and in this case even fire.

Bill

[Bob Dodge]

Bill,

Thanks so much for pointing out how wrong I am,,,,, again.

I feel "enlightened".

The competition and animosity that accompanies a lot of dc threads, just never ceases to amaze me. Why can't people, simply discuss these things dispassionately.

Sorry Bill, you're on your own. Not gonna "go there".
-----------------------------------------------------------------------
Oh, What the hey, just one point:D

The first two paragraphs you wrote, along with the "quotes", directly contradict each other. I'm not certain you noticed.

In paragraph 3, you state;

This dc is "engineered", to move a maximum of 966 CFM at just over 4" sp......... Well yes. They ALL are:D . That's precisely the point at which 2 bhp is produced by a moving airstream. To be a little MORE specific, it's 2.03 bhp, with a static efficiency of 32%. That sir, raises two points.

first, the dc could move THAT load, at THAT resistance. it can also move MORE CFM, at LOWER STATIC PRESSURE, and achieve EXACTLY THE SAME bhp.

Example....1275 CFM, at 3" sp = 2.03 bhp
Conversely, 645 CFM, at 6"sp, ALSO equals 2.03 bhp.

Second.(and with your "knowledgeable background and engineer/professor/doctor/hygienist friends,should know this) How do you get 2 bhp, out of a 5.6 amp/220v motor ????????????????????????????? Understand now, why I said this dc is set-up for low static pressure operation???????

So much for "engineering"

Bob

[Ken Salisbury]

OK Guys ! ! ! you're at it again


Don't make me start editing/deleting again. Please take this issue off-line


http://www.oldrebelworkshop.com/misc/moderator.gif

[Stu Ablett in Tokyo Japan]

Ken, I have an honest question for you.

If member "A" notices a post by member "B", that has information in it, that to the best of the knowledge of Member "A", is incorrect, can member "A" point this out and correct it?

Just wanting to know.

BTW, I find this a very interesting thread, yes is it a bit contentious, and the posters have to be careful to watch it, but a good read and has a lot of information in it.

When someone challenges your ideas, and or research, and you have to defend it, this exchange makes for good reading and lots of exchange of ideas.

I do agree, we do not need the personal attacks.

Cheers!

[Jim Becker]

If member "A" notices a post by member "B", that has information in it, that to the best of the knowledge of Member "A", is incorrect, can member "A" point this out and correct it?

Of course...nicely and with the reasons for the error. "You're wrong!" doesn't cut it. "You're wrong because..." does. Said nicely. Healthy debate is good. Attacks are not.

[Jim Chilenski]

OK, so now I'm even more confused. Nothing new really. Are you saying if I were to remove all resistance from my dust collector, take the blower off of the drum and remove the filter bag that my motor would burn up? :eek:

"Otherwise, you'd overload the motor.
Although you mean well, you were not clear that this motor was equipped with a vendor intentionally oversized impeller to meet an already known high resistance. In this case anything a person does to reduce that resistance below about 4” puts the motor at risk of trying to move too much air causing it to overheat and burn out. Just putting on a higher airflow fine filter can put this unit at risk if you reduce the resistance below 4.1”."

Would the same thing happen if I were to run the blower with all of the blast gates closed? I don't have an amp meter and I'm not a triple-E, so I'm trying to understand what you're telling me. Please explain.

Thanks,
Jim

[Allan Johanson]

OK, so now I'm even more confused. Nothing new really. Are you saying if I were to remove all resistance from my dust collector, take the blower off of the drum and remove the filter bag that my motor would burn up? :eek:

Hi Jim,

DC blowers work harder with the more air they move. If all the blast gates are closed then it isn't flowing any air so it isn't doing much work. No worries there.

But if the resistance drops (like removing restrictions so it can flow more air), then the "work" increases and the motor load increases with it.

Here are some sample numbers with a typical 2HP DC where I slowly allowed it to flow more air:

211 cfm @ 6.6 amps
480 cfm @ 8.2 amps
634 cfm @ 9.0 amps
712 cfm @ 9.4 amps
746 cfm @ 9.6 amps
810 cfm @ 10.0 amps

But the problem is the DC has a motor with a max of 9 amps on the nameplate. Allowing it to breathe freely with a short length of pipe caused it to draw more current than the motor would like.

Bill is right.

Cheers,

Allan

[Stu Ablett in Tokyo Japan]

Jim, the way it was explained to me that made sense was to look at the blower as a pump, it pumps air.

If I close all the blast gates, the blower is not pumping anything, it sounds like heck, makes all kinds of weird noises, but it does not hurt anything. The blower is just spinning around not pumping.

If you have very little or no resistance, the blower is taking bigger and bigger bites of air to pump, thus it draws more amps, it left unrestricted, it will draw more amps than it is rated for, and burn up.

Does that make sense?

I know it is not in any kind of technical terms and or language, but sometimes that just confuses us laymen.

Hope it helps

Cheers!

[Julio Navarro]

What about stalling? If the fan is not moving any air can it move? wont the static preasure slow down the motor enough to stall/stop it?

If you have a tunnel effect where the fan cant draw any air from anywhere wont it create enough of a vacumn to stop it?

[Alan DuBoff]

Alan,

What about building a cyclone, less the ducting, and connect it directly to the tools? Will that work reasonably also, or does the cyclone need more ducting? That would also allow for adding in ducting later to supplement the system.

If you go with the 14” impeller, nice Leeson 5 hp motor, and cyclone with minimal ducting you will be fine. The 15” impeller needs the extra overhead of the ducting to ensure not pulling more than the 5 hp that motor can provide.Ok, I might have a line on a Delta 50-853, which has a 3HP 220v single phase motor, and a double stack, I think it's single stage, but not sure. Marketing litterature says 2100cfm, would that get me 800cfm if it was connected directly to a single machine?

This might satisfy me and may be able to be used if I wanted to build a cyclone, but probably wouldn't be as powerful as a 5HP.

Any thoughts Bill?

Can the cloth bags be replaced with canisters at a reasonable price? Can canisters be built for a unit like that? I'm thinking of how I could get something like that down to .5 micron if I can pick it up at the right price, if it would hold me until I can build a cyclone.

[Jim Chilenski]

Alan / Stu,

Thanks for the replies. Less technical explainations work much better for me. Let me see if I can take this a little further. If I were to remove my duct work and the drum that my collector sits on there wouldn't be any resistance and the blower would move more air but would burn itself up. So a blower NEEDS to have the resistance that's created by the duct work, and in my case the first stage seperator, so that it doesn't burn it up the motor?

But if I close all of the blast gates the motor won't burn up because its running in a vacuum and doesn't have any air to push, so there isn't a load on it.

Thanks,
Jim

[Jim Becker]

Jim...correct. In fact, the cyclone manufacturers like Oneida caution you to not run the system without duct work attached in big, bold letters for exactly that reason.

[Bob Dodge]

Jim,

Basically, it goes like this.

Your blower has a 5.6 amp motor. Now, unless someone's come up with a new way of getting over 100% efficiency in that "2 hp motor", there's not a hope-in-hell you'll handle a 2 BHP airflow. Forget it. It won't happen.

What Bill stated, has to do with the "combination" of CFM, and STATIC PRESSURE of a moving "air column". When Bill says 966 CFM "AT" 4" sp, that's the bhp of that airflow combination, but, as I said above, you can move a lot MORE air, at a lower static pressure, or, a lot LESS air, at a much higher static pressure, and produce the SAME bhp.

Let me give you an example. I have here, a large airfoil blower. It's a SW/SI (single-width/single-intake) 15-16.5" airfoil. It's also belt-drive. Now, that blower, in it's current configuration, pulls somewhere between 2400 and 2700 CFM. It also does this at a very low static pressure, probably around 1" sp. The pipe flange, is for a 15" pipe. Now, that blower is powered by a 1/2 hp Leeson motor, turning at 1725 rpm. 1/2 hp/ 2700 cfm. Think about it. This is why you can't simply look at "air volume" (CFM) as the determining factor for BHP. It's the combination of "both".

If I wanted to use that blower for a large down-draft table for example, and I wanted to move roughly the same amount of air, but at a higher static pressure, I'd have to do two things. Increase the rpm of the blower, then, reduce the inlet diameter. That's it. It's that simple. Now, I'd be moving roughly 3000 CFM, but at 3"SP. That may sound like a lot, but it only requires something like 2.6 BHP. I need to upgrade the motor to a decent 3hp motor, and provide the correct pulley to the fan-wheel shaft.

Now, with Jim's blower, he has that 5.6 amp motor, and his fan-wheel is a decent 12 1/4". It's also turning at a "fixed 3450 rpm". He has a 6" inlet. Can he pull 966 CFM at 4" SP??? He'd burn his motor. No Can Do. So, HOW, do you handle that situation, yet keep that suction level at a reasonable level. Simple. You control it at the outlet.

By providing a restricted filter-surface area, back-pressure is increased. That back-pressure, known as "pressure-drop", "DROPS the inlet suction pressure correspondingly. Jim's 6" pipe would still flow enough air to get the necessary velocity in his pipes, but not high velocity. It would be "adequate", and stay within the motor's limitations. The combination of CFM and Static Pressure, would have to be below the motor's full-load amperage. He might for example, pull 800 cfm, at 4076 FPM in his 6" pipe, at a static pressure of 1.515"sp. That would be the resistance of a 10 foot galvanized-metal pipe, w/ 6" diameter, and a bell-mouth entry. BHP requirement with a fan that has a 32% Static Efficiency, would be only 0.6 BHP. Welllll below his 5.6 max amp-draw threshold.

If he adds a larger filter surface, that will lower his back-pressure, and his suction will increase, BUT, it could overload the motor. What do you do about THAT???? Simple, you provide the necessary resistance on the intake side of the blower. In otherwords, by connecting the appropriate pipes you'll increase resistance where it's doing you the most good. He'd flow perhaps less air at some machines (small machines/smaller ports), or more air, at lower velocity(SP), in larger pipes.

It's all a simple matter of proper "balance". You have to balance amp-draw/CFM/Velocity(SP).

Bob

[Bill Pentz]

OK, so now I'm even more confused. Nothing new really. Are you saying if I were to remove all resistance from my dust collector, take the blower off of the drum and remove the filter bag that my motor would burn up? :eek:

Jim,

Sounds like you have a pretty good hadle on what is going on. As Allan Johanson showed in his chart you are exactly correct, take away the reistance of your drum separator and the increased airflow will burn up the motor unless you ensure your system elsewhere adds enough resistance.

How I came up with this unti needing about 4" is pretty important if you are serious about ensuring you have a big enough blower to power dust collection in your shop. To size a blower motor we can compute the hp it takes to move a given CFM then add the hp it takes to overcome the resistance in your system. Alternatively, if we know how much CFM we need we can then estimate how our maximum resistance, then look up in a fan table what hp motor we need, optimum impeller size, and opening for our blower which also turns out to be our optimum ducting diameter. For the motors we round up to the next motor size without having to get a custom motor built, e.g. 1, 1.5, 2, 3, or 5 hp for most small shop sized dust collectors. The fan table tells us what sized impeller makes best use of that motor without allowing it to move so much air it causes the motor to burn up.

In the case of your blower Cincinnati Fan based dust collector, we can work backward to see exactly where this unit was targeted. It has a 2 hp motor, 12.25” diameter impeller, and 6” blower opening. Checking the Cincinnati Fan Tables for their steel pressure blowers shows this impeller pulls 2.03 hp at 4” resistance moving 966 CFM. I know Cincinnati Fan is one of the leaders in this industry and am comfortable they sized this motor and impeller appropriate for this dust collector. That means they knew this dust collector would always have more than 4” resistance. If you go with less than this 4” you will move more air, but will soon burn up this light duty 2 hp motor which is at the bottom of the 2 hp amp range. The good news is you could easily use a heavier 2 hp or even 3 hp and it will mount in the same holes and avoid this problem with less resistance and larger airflow.

[tod evans]

hey you guys! both of you are assets to the creek but when ya`ll get started with the techno jargon you`re loosing about 90% of us and getting each other upset in the process.......no gain for anyone ....02 tod

[Alan DuBoff]

With that said, I had asked a pretty basic question, wether a Delta 50-853 would function as a decent unit to connect to a single woodworking machine at a time, and if it would have enough cfm to collect fine dust at around 800cfm. Could this handle 2 machines at a time with reasonable suction? Could I use the motor to build a cyclone if I desired in the future?

I've run across a reasonable price on such a unit, and I'm trying to figure out if this unit will do ok for the interim. I think it will, it has a 230v 3HP single phase 3450rpm motor, which Delta rates at 2100cfm (whatever that gets me), and it looks like I could replace the bags with Wynn Environmental cartridge kits. They list the 50-850 as working with some angle clips, maybe the 50-853 is similar. That might require a call to Wynn Environmental (or email). Please feel free to comment Bob, but please don't include Bill's name in your response. In fact, please do not even refer to him. How much cfm should I expect at the machine, single 6" hose, or single 4" hose.

[Allan Johanson]

Hi Alan,

Thanks for the ignore reminder. I tried it out and all the goop is gone. Back to a clean thread and I can still read Bill's posts.

For this Delta DC, does it have a 13" fan? What kind of filter bags are on it? Crummy 30-micron ones or better felt ones?

If it does have a 13" fan and crummy bags I'd still consider buying it if the price was right and if I couldn't do a cyclone right away. I'm not a big fan of stuffing a cartridge filter on a single-stage due to potential clogging issues so what I'd probably do is build a box around the filter bags (and buy some better aftermarket bags) and stuff the cartridge filter in the box so the air had to flow through the blower, into and through the filter bags, then go through the cartridge filter and back to the shop. Now you'll have a 2-stage filter setup where you have easy filter bag cleaning (rig up a remote bag smacker to release a dust cake if required) and this will help protect your cartridge filter from a vast amount of dust.

Is this the ultimate DC? Nope. But it can get you flowing a decent amount of air hopefully fairly quickly with fairly decent air quality results with the easy maintenance 2-stage filter approach.

It's one option, anyhow. :D

If this blower was to be used on a cyclone then the performance might be like the woodsucker. That cyclone had a 13.13" fan. It should deliver 800cfm with a short 6" duct run. The single-stage version should deliver more airflow.

Stick with 6" runs if you can. With 4" drops you'll probably be looking at airflow ranges in the 450-600cfm range with a moderate to short duct run.

It's just a ballpark guess considering there are way too many variables.

Cheers,

Allan

[Bob Dodge]

Mr DuBoff,

There is no Delta model 50-853. Are you perhaps referring to the Delta 50-763 hp model?
http://www.deltamachinery.com/index.asp?e=136&p=5818



Bob

[Ken Salisbury]

Some folks won't even listen to a warning given as politely as I possible could, yet the war continues.

Continuing to bash each other could result in suspension of both Bill and Bob from this forum. any further such conduct will result in my making that recommendation to the SMC Administration.

This thread is now closed to further posting. I will closely monitor any new threads on the subject and take appropriate actions to insure our Terms of Service are adhered to.


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