# Cyclone question



## demilio (Jan 16, 2021)

Background: I have a HF dust collector that I upgraded with a Wynn filter and have been considering converting it to a 2-stage system with a Thien style separator. Space is at a premium in my shop though so I have been trying to think up a design that would give me most/all the benefits of the 2-stage system but with a smaller footprint. I do have plenty of vertical space to work with as my ceiling is at least 12 ft high. 

As I think about this, it seems that the plastic bag is a relatively inefficient use of space given that very little dust should end up there vs the barrel under the separator. What if instead of the bag, there was something like a chute underneath the filter that tapered very quickly down to a 4" pipe? I'm imagining something where I can then mount my filter up high on the wall and have the excess dust fall down the pipe to a small bin on the floor rather than using a bag. Or maybe I could even have it go from the pipe into the same barrel under the separate with a blast gate I keep shut when it is running?

It seems like this should work in my head - am I missing any design flaws?


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## Crispy (Dec 28, 2020)

demilio said:


> Background: I have a HF dust collector that I upgraded with a Wynn filter and have been considering converting it to a 2-stage system with a Thien style separator. Space is at a premium in my shop though so I have been trying to think up a design that would give me most/all the benefits of the 2-stage system but with a smaller footprint. I do have plenty of vertical space to work with as my ceiling is at least 12 ft high.
> 
> As I think about this, it seems that the plastic bag is a relatively inefficient use of space given that very little dust should end up there vs the barrel under the separator. What if instead of the bag, there was something like a chute underneath the filter that tapered very quickly down to a 4" pipe? I'm imagining something where I can then mount my filter up high on the wall and have the excess dust fall down the pipe to a small bin on the floor rather than using a bag. Or maybe I could even have it go from the pipe into the same barrel under the separate with a blast gate I keep shut when it is running?
> 
> It seems like this should work in my head - am I missing any design flaws?


Wouldnt air from the DC blow the dust into the shop?
I am going to mount the blower on my shop ceiling and vent it outside behind my garage and let the dust blow into the woods. I will also have a cyclone to catch almost all of the chips and dust. Just what would end up in the bag will be blown outside.


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## demilio (Jan 16, 2021)

The air would still go through my filter, just instead of a bag under the filter the fine dust not caught by the cyclone would fall down the chute.


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## DustyDan (Dec 21, 2020)

I’m still using a shop vac with a cyclone separator so this may be a dumb comment about how a dust collector works. But when you say the fine dust will fall down the chute, doesn’t that really mean it will be “blown” down the chute towards a trash can? I’m picturing placing the equivalent of a small fan blowing into a trash can filled with flour. I thought the bag sees enough back pressure to stay “inflated”. Seems like an open chute would have enough airflow to defeat the purpose of dust collection. Don’t be afraid to tell me I have a gross conceptional error in my thought process. I’ve been wrong before. Just ask the love of my life.


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## demilio (Jan 16, 2021)

DustyDan said:


> I’m still using a shop vac with a cyclone separator so this may be a dumb comment about how a dust collector works. But when you say the fine dust will fall down the chute, doesn’t that really mean it will be “blown” down the chute towards a trash can? I’m picturing placing the equivalent of a small fan blowing into a trash can filled with flour. I thought the bag sees enough back pressure to stay “inflated”. Seems like an open chute would have enough airflow to defeat the purpose of dust collection. Don’t be afraid to tell me I have a gross conceptional error in my thought process. I’ve been wrong before. Just ask the love of my life.


Chute is probably the wrong word. It would be an enclosed pipe with no exit for the air. That is a good point though, there is enough air pressure to inflate the bag so my pipe would need to be sealed pretty tight so air didn't get out.


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

DustyDan said:


> doesn’t that really mean it will be “blown” down the chute towards a trash can?











Heavy stuff would "drop down the chute" just like it does with standard set ups. The fine dust either needs a filter or a vent outdoors. The outflow of air is the same speed as the inflow of air that we call "vacuum." Restrict the outflow ... gets less "vacuum".


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## DustyDan (Dec 21, 2020)

My original








mikechell, Thanks for the explanation and drawing. I added a little. My original understanding was that demilio (OP) was going to modify the system by adding a chute where the plastic bag would traditionally be. This chute would direct the heavier stuff to the trash can rather than the bag. I saw this design as flawed since the path of least resistance would be to the can and not the bag filter. Airflow and dust would flow into the can and spread in the shop. However, the OP corrected me and implied that rather than an open chute, he intended to include a blast gate (or similar) that could be emptied into a can as needed. I think that design may work.


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## HoytC (Dec 30, 2019)

demilio said:


> Background: I have a HF dust collector that I upgraded with a Wynn filter and have been considering converting it to a 2-stage system with a Thien style separator. Space is at a premium in my shop though so I have been trying to think up a design that would give me most/all the benefits of the 2-stage system but with a smaller footprint....


Rather than _add_ the Thien style separator _convert_ your existing separator to Thien style. That is, add a baffle to the bottom of the ring that holds the bags. You won't increase the footprint of the system and you'll have less loss in airflow performance.

Another approach is add something similar to Jet's Vortex Cone. You can buy the real thing, fabricate something from sheet metal, or repurpose something like a wok.

There's lots of information available on these conversions. Some good search terms:

"dust collector wok mod"
"add vortex cone"
"adding internal thien baffle to dust collector"

Of course none of these will work as well as adding a SDD cyclone and going straight to the filter from the blower (no separator ring).


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## demilio (Jan 16, 2021)

DustyDan said:


> My original
> View attachment 423701
> 
> mikechell, Thanks for the explanation and drawing. I added a little. My original understanding was that demilio (OP) was going to modify the system by adding a chute where the plastic bag would traditionally be. This chute would direct the heavier stuff to the trash can rather than the bag. I saw this design as flawed since the path of least resistance would be to the can and not the bag filter. Airflow and dust would flow into the can and spread in the shop. However, the OP corrected me and implied that rather than an open chute, he intended to include a blast gate (or similar) that could be emptied into a can as needed. I think that design may work.


Thanks, this is exactly what I was thinking.


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## demilio (Jan 16, 2021)

HoytC said:


> Rather than _add_ the Thien style separator _convert_ your existing separator to Thien style. That is, add a baffle to the bottom of the ring that holds the bags. You won't increase the footprint of the system and you'll have less loss in airflow performance.
> 
> Another approach is add something similar to Jet's Vortex Cone. You can buy the real thing, fabricate something from sheet metal, or repurpose something like a wok.
> 
> ...


Interesting, I hadn't thought of that. Thanks!


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## thegrgyle (Jan 11, 2011)

This is what i did for my space saving dust collecter... i put my thein separator under the impeller/intake port, and then put a very short bag under the wynn filter side... so that i could put a small cabinet to store alot of my various dc accessories...


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