# pictures



## gmcooter#2 (Oct 22, 2016)

I took some pictures of my dust collector. I'll see if I can get them posted


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## Toolman50 (Mar 22, 2015)

It's not pretty!
Does it work well?


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## woodnthings (Jan 24, 2009)

*another shop built blower*

Have you seen this?





He's a smart feller, for as young as he seems to be. :smile3:

Apparently there is more than one...


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## gmcooter#2 (Oct 22, 2016)

I know it would not win a beauty contest. I'm an amateur at fabrication with metal. I just used what I had to do what I wanted to try. I don't have any way to measure CFM or static pressure or any of that stuff. I am just going by what it picks up. It emptied the box under my table saw and picked up saw dust off the floor. I blew off all my machines and had it so dusty in the shop you couldn't hardly see. I turned the collector on and in a very short time it cleared the air very good. That was what I was trying for so I'm pretty satisfied. I have it in a room off to the side of the shop so you don't see it only when I open the door. Thanks for your reply. I've been getting some negative response about building my own. Take care


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## gmcooter#2 (Oct 22, 2016)

That is a big one alright. He did a nice job.


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## m.n.j.chell (May 12, 2016)

That's a nice project ... and the fact that it works is credit to your abilities. Making an impeller that is balanced is no small feat.

Well done !!!


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## Carl10 (Feb 3, 2017)

Excellent! Now we can see your creation. It is hard to determine the original scroll shape of the housing from the pictures but it appears to be like the image I have attached. The one image shows a very flat front housing (where the exit opening is flush with housing). This is typical of a furnace blower housing. Compare this to a typical dust collector/Cyclone blower housing (second picture) and you can see the basic housing scroll differences. The furnace blower housing has a low cut off point (gore point) that is very low (just above the half way point of the impeller). The dust collector blower has a higher and recessed cut off point. So although you have changed the impeller, motor and housing width, you still have a furnace blower housing scroll (sorry woodthings - if it quacks like a duck.....) This and your new exit port opening is too low.

Try raising and enlarging (~6-8" diameter but rectangular in shape the width of your housing) your exit port. If the opening does not go to the top of the housing try and add some sheet metal (even a wood wedge) to gradually direct the air down from the top to the edge of the top of the opening. (You dont want the air blowing right into a perpendicular surface) That should help quite a bit, but your aerodynamics on the exit is still going to hurt you. You have done the hard part by making your own impeller and paired it up with a good motor. I would suggest making the Bill Pentz blower housing and you will see a significant difference. The plans are free and scale-able. His plans are designed for a 14" impeller. Just reduce down your printer output to match your impeller diameter. I plan to do this very project in the coming weeks for an impeller/motor I just bought.

Let us know what you do next!

Carl


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## Toolman50 (Mar 22, 2015)

Toolman50 said:


> It's not pretty!
> Does it work well?


If works good, that's all that really matters to become a nice addition to your shop. 
Very creative with the wooden blades. :thumbsup:


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## gmcooter#2 (Oct 22, 2016)

Thanks Carl. That wouldn't be hard to do because the front plate bolts on. I sealed it with silicon caulk that's the hardest thing to break loose. I've all ready had it back off once already. The impeller slipped loose on the shaft so I had to take it off and the inlet port to tighten the impeller. I have the Bill Pentz article. I printed it off before I started. I guess I misunderstood that part. I'll try that and see if it improves it. I's doing pretty good as it is but that could improve it more. Thanks again for your advise. Take care.


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## woodnthings (Jan 24, 2009)

*blower housing design questions*

Does anyone know what the air speed/velocity is around the upper or lower portions of the outlet? How critical is the distance from the side of the impeller blades to the housing? Is closer better? How do you know what spacing to use?










We can see that the spacing from the tips of the impeller blade increases as it exits the blower housing/volute. I suspect that this allows for it to be compressed initially, then expand as it exits, but I have no clue really. Like I said previously, air flow is a science unto itself and I give credit to anyone who wants to jump in with both feet and make their own system! :smile3:


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## gmcooter#2 (Oct 22, 2016)

My impeller fins are 3" high. I left about an inch between the highest point of the fins and the housing. I can't say weather closer is better or not but mine is working pretty good. Carl said I needed to modify my outlet a little. I may try it a little later but it's doing pretty well right now. I need a brake from it for a little while It's about wore me out. I started a tow truck model today. When I get it done I my give another try.


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## Carl10 (Feb 3, 2017)

Woodthings,

The velocity of the air is based on the diameter and RPM, so for a 13" diameter impeller

V=Circumference * RPM 
=(D*Pi) * 3450
=((13*3.1416)/12) *3450
=11,741 FPM

That is theoretical so you can use a 80% for real world.

The impeller distance should be about 10% of the impeller diameter away from the cut off point. That is a balance between efficiency and noise. The gradual increased distance from the housing can be represented by an Archimedes spiral. You can also calculate a radius for points on either side of the fan center to make housing shape.

Like you, I am an ex automotive engineer, but the book Centrifugal Fans for the Home Shop by David Gingery is a great reference for learning about these fans.

Hope this helps,

Carl


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