Is this a suitable blower for a dust collection system??? It really blows

Wondering if this blower is usable in a dust collecion system. Looks about right to me but I'm asking the experts here. Pictures are at:

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are: diameter 11 inches. Opening in housing with cover removed as pictured is 8 inches. Opening in cover shown in last picture is 4 inches. Outlet is 2 1/2 inches. Motor is an AO Smith 1/2 HP 9.5 amp motor at 115 volts or 4.8 amps at 230 volts and 3450 RPM It was installed in an air sampleing system and was adjusted to provide

1000 CFM through a 4 inch pipe. It will do more than that as the outlet was restricted with a gate valve to get the 1000 but I don't know what the max is. I ran it briefly with the cover off as pictured and I could feel the suction when I got close. It was scary. What do you think, worth a shot? Meanwhile I'll DAGS and see what else is involved with a homemade collector. One final question. Noise issue and sawdust piles aside, could a dust collector just be vented outside rather than into a bag or chip collector. Thank you kindly gentlemen
Reply to
Mike in Arkansas
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I don't see why not - what have you got to lose by giving it a try?

Sure as long as you don't mind the dust settling on everything in the immediate area.

Reply to
Fly-by-Night CC

Reply to
JGS

I faced the exact same situation a few years ago. I had a blower, very similar, from an old forced hot air furnace. I decided I could convert it into a dust collector. The short of the story is that I spent neary $100 dollars, wound up frustrated, wasted a lot of spare time that I could have been WWing with, or installing a real DC. If you are planning to build a portable unit, that might be one thing, but if you want to have a centalized system at all (i.e. running ducting to your machines) you'll find that 1/2 horse (despite the fact that it feels like it has a lot of suction) is way underpowered. I eventually spent $150 on the harbor frieght 2 horse, 20 amp unit, and like a lot of people, I am very satisfied with it. Once you hook up any lengths of ducting to that thing you've got, you'll soon find how inadequate the power will be. I also believe you write that your's has only a 2 1/2 inlet??

I only say this because of my personal experience trying to do exactly what you are considering. Don't bother!

Mike > Wondering if this blower is usable in a dust collecion system. Looks

provide

pictured

outside

Reply to
Doug

Sure can, but there are other issues. Wife, neighbors, open windows on your car, When I bought my Delta planer I did not have a duct collector. I figured I try running it outside the garage. I planed one board and bought a DC. There was chips all over the place. Your DC will do the same and make an ugly looking mess. If you happen to live in a cave near the town dump, go for it. If you live in a decent house, well, you get the idea.

Reply to
Edwin Pawlowski

On Sat, 12 Feb 2005 01:16:32 -0800, the inscrutable Fly-by-Night CC spake:

Wait'll his wife hangs the laundry while he's in the shop...

-- Vidi, Vici, Veni ---

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Comprehensive Website Development

Reply to
Larry Jaques

I would use it. The expensive part of a DC is the impeller. Yours is bigger than normal, and the bigger the better. Sure, the motor is too small, but you can always upgrade that later.

Reply to
toller

Okay, okay, venting to the outside is out :) Going to plan to use but Im a little confused about horsepower. If it will move more than 1200 CFM now at 3450 RPM with 1/2 hp, how will increasing the hp help? Seems like a lot of the DC's are rated at less than 1000 CFM. Do I need the hp to overcome piping length? Thanks for everyones input

Reply to
Mike in Arkansas

My guess is the blower you have is rated free standing, not configured into a machine that will cause static pressure and require more power to move the same cfm. When you put some tubing and bags on the other end it would make a difference.

Reply to
Edwin Pawlowski

I'm not sure where you're getting your CFM rating. It seems very high. When I tried to build mine, the problem was not that the motor could not turn the impeller enough to create a lot of wind-- it did! But I soon discovered that the motor was drawing too many amps and it eventually would begin to overheat. It was simply being strained. And yes, as you add ducting, you will increase the stress on the motor.

I suppose if you were thinking about just blowing all of the dust out the window, it might be worth a try. I was trying to contain the dust, so my added expenses included an attempt to add DC bags, etc. .

Again, though, if the whole thing is going to funnel down to 2 1/2 inch inlet, I really just don't think it will be too effective. Good luck. I'd be curious to see if you can make it work without too much frustration or expense. Let us know.

Mike > Okay, okay, venting to the outside is out :) Going to plan to use but

Reply to
Doug

Centrifugal blowers are a little counter-intuitive. Adding restrictions to the input or outlet will actually reduce the load on the motor. Try it on your shop vac. Plug the hose and listen to the motor speed up slightly. If you had an ammeter hooked into the power circuit, you would note a drop in current with the inlet hose blocked.

Motor current consumed by a centrifugal blower (or any fan, for that matter) is directly proportional to the amount of air being moved. If the air flow is reduced, so is the motor current. Adding filters, ducts, gates, etc. will reduce the CFM of the system, and drop the current demand of the motor. It would run cooler.

It would actually put more load on the motor to run without bags, etc. See above.

The impeller is a little small compared to most commercially available collectors, but could work if only one tool is in use at a time. Since both the impeller and its housing appear to be made from aluminum, running it without a cyclonic separator could result in some rapid erosion. It does have a substantially larger impeller than most shop vacs, so it should produce higher CFM than they would.

Your CFM will be limited by impeller size and speed, not motor HP. Speeding up the impeller probably won't help much, and at some point will actually reduce airflow. Your motor and impeller seem well matched, and added restrictions will actually reduce the load on the motor. See above.

Dust collection systems SHOULD be rated as used; that is, with filters, ducts, gates, etc. in place. Free air ratings would be of little use. Your CFM may drop considerably when all that stuff is connected to the blower.

Dale Scroggins also in Arkansas

Reply to
Dale Scroggins

On 11 Feb 2005 20:08:47 -0800, "Mike in Arkansas" vaguely proposed a theory ......and in reply I say!:

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Unless there is some magic at work here, that is the stopper. Most halfway decent DCs _start_ at a 1 HP motor. 2HP is better. 1HP ones would service maybe 2 machines, but are best wheeled around the shop to each machine. I think that you will find that the fan part of this will be designed to load the motor OK, but not to move the air needed to be a DC.

On the other hand, if it was getting 1000 CFM through a 4" pipe.... shrug....magic.

Could somebody expand on that for me? Maybe it just moves huge amounts of air, but with no real pressure?

Reply to
OldNick

On Sun, 13 Feb 2005 22:28:39 GMT, Dale Scroggins vaguely proposed a theory ......and in reply I say!:

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Agreed, and all most unfair!

Reply to
OldNick

This blower should work with the cover but the motor is small. Maybe if you get a drum with a cover. In the cover have an inlet from your machines and the outlet hooked up to the blower. At least the large particles should stay in the drum and only the finer particles would go through the the blower. All those heavy particles could quickly kill that small motor.

One guy mentioned a furnace fan, those are squirrel cage fans and will not work on any solid particles. They are made for air only. The shavings and other large pieces would get caught in the fins and quickly make it out of balance.

Reply to
Eric J. Comeau

Mike...

Nobody seems to have suggested it yet, so I'll give it a whirl. You ought to take a look at Bill Pentz's page here:

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might even try emailing Bill and tell him what you want to do. Getting a good air mover seems to be the crux of building a good DC setup, and while yours sounds underpowered for even one machine, you could put a 1.5 or 2 HP motor on it and combined with a cyclone, you'd have a very efficient and powerful system.

You might also want to look at this:

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you can buy a 3/4 HP DC unit complete with bag at Lowes for $99, so before you go nuts, look around.

Mike

Reply to
captmikey

Okay, my apologies. I am an uneducated dolt that has CRS real bad. Memory failed and the 1000 CMF figure I was quoting was actually 1000 feet per minute VELOCITY. Since this was 1000 feet per minute through a

4 inch tube, I believe that works out to about 85 CFM. Managed to get my hands on a spec sheet for this blower and maximum CFM free delivery is only 350 CFM. So those that said it was too small for a shop wide DC were correct. Dang! As always, I appreciate very much the input from everyone.
Reply to
Mike in Arkansas

On 12 Feb 2005 09:52:37 -0800, "Mike in Arkansas" vaguely proposed a theory ......and in reply I say!:

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Ok. I have been giving this some thought.

When you add piping, the power use will _drop_.

But if you add piping, the flow will also drop.

Machines not drawing any air need very little power to run. The motor is essentially idling.

The only way I can see that your 1/2HP machine was dragging 1000CFM (if that's what you actually saw it do) is that it is doing it only at extremely small pressure differentials. This will have to do with the design of the fan. I am not up with the finer details, but have looked at water pumps a bit. Rotor design is critical to decide high flow, high pressure etc. Either can be done with lower horsepower, if the other is largely ignored. For instance there are bilge pumps that move huge quantities of water, say 400 - 200 GPH, drawing only a few amps at 12V. But their lift is maybe 3-4'.

Your setup may draw the claimed 1000CFM through the 9" opening without any ducting.

Had a look at some tables (neat little set of software charts called Engineering Power Tools). According to me, to drag 1000CFM of air through 60' of 4" pipe would need 3.5 Hp straight and 5 Hp or more with 3 elbows.

So adding HP may _not_ work. You will still spin the blower at the same speed, and it will still move its 1000CFm, but when you add piping (= "head" of pressure) you will simply not suck anything.

I would suggest getting a longish length, say 2-3 x 20' of 4" storm pipe and a couple or three of elbows, and see what happens when you try to draw through them. If you are happy then you are happy, and I need to rethink my above BS!

Reply to
OldNick

On 14 Feb 2005 14:48:21 -0800, "Mike in Arkansas" vaguely proposed a theory ......and in reply I say!:

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gaaah! I just spent a half hour sorting ouyt and posting a great deal of stuff!

Reply to
OldNick

Sorry about that OldNick. Your critical thinking was appreciated and spot on. I still might try using it as a single machine DC for a jointer or planer. Put a bag on the outlet and mount it on a trash can seperator and see what happens. Again, Im sorry, I did not intend to make anyone waste their time. In fact, I knew about the 1000 fpm velocity figure because I had need to work on this very problem just a couple of months ago using this very fan. Using a pitot tube and micromanometer, I adjusted the outlet restriction to produce the said velocity in an air sampler system. To quote you "gaaah"! Mike in Arkansas who as he nears the age of 60 is losing his frigging mind.

Reply to
Mike in Arkansas

On 14 Feb 2005 21:07:14 -0800, "Mike in Arkansas" vaguely proposed a theory ......and in reply I say!:

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I was just kidding. It was an interesting exercise. I thought it was rather good. Everybody running around trying to work out HTF, and nobody even came up with the 1000FPM!

Only comment is, use as big a bag as you can. My 1HP unit has two bags, maybe 2' high and 18" diameter?? It's still only considered a

1-machine machine. The bigger the bag the better the suction for a given fineness of mesh.

Reply to
OldNick

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