An inline separator idea

[phil (admin)]

I posted this in another thread but figured I'd create a new thread.

I'm including a pic of my "inline separator."  It has about the lowest pressure drop you can achieve.

One thing you need to know...  When a vacuum is pulled on a pipe, the air moves fastest through the center, slower at the edges.  This means the pipe itself is acting like a separator.  I can watch this with my clear pipe network, I see the bulk of the debris swirling around the outside and trying to stay out of the way of the faster moving air in the center of the pipe.

So in the pic I'm attaching, the gadget's left side is attached to my (or your) ductwork.  On the right side is a smaller pipe to which suction is attached (I use a shop vac but this can be scaled-up to larger blowers).  This extends through a sealed cap and past the end of the wye.  This smaller suction pipe is the vortex finder.

So now what happens is that the suction forces the dust in the pipe into a spin.  Once it arrives at the vortex finder, it can't reverse direction fast enough and passes the finder and continues into the Wye, where it is directed down into a discharge.

One downside to this method is that you have to size it so the largest expected bit of debris can fit between the inside, and outside pipes.  That is true of systems using my baffle, too.

One other downside would be lower separation rates.  I think.  I'm not positive on that.  There are quite a few variables like, how far should the finder tube extend past the wye's 45-degree leg?  And on units designed to accommodate larger DC units, can offsetting the finder improve separation?

It works way better than anyone to which I've demonstrated it would have thought, though.

And there are numerous advantages.  Takes up almost no additional space you haven't already lost.  And limited ceiling height isn't a problem.  Very little pressure drop, too.  Not too difficult to build even in larger sizes.

I need more time to experiment with it.

[tvman44]

Anxious to see the results of further testing.

[clydeone]

Where does the Wye discharge to?  A trash can?  Interesting I wonder if you could use this in series with your Thein separator to improve dust removal?

[phil (admin)]

Where does the Wye discharge to?  A trash can?  Interesting I wonder if you could use this in series with your Thein separator to improve dust removal?

Yep, for that test I just had a long (36") straight tube with an end cap on it (makes fairly decent measurements possible).  But ultimately, it would drop to a drum or box or whatever.

[retired2]

Pretty clever Phil, but I'm thinking about how that would scale up for use with a 1-1/2 hp DC.  For example, I'm already plumbed with 5" pipe throughout for my Delta DC.  So, if I installed a 5" wye just ahead of the blower I would only be able to use a 2-1/2" or 3" outlet.  That would then transition to the 5" inlet size of the blower.  I'm not sure how well that would work.

The other alternative is to use a 5" outlet pipe and replace all the plumbing with something like 8".  Even if I were willing to do that, and I'm not, I don't think I could mantian enough velocity at that size to convey the waste.

Never the less, I'm anxious to see how your testing and fine tuning works out.

[phil (admin)]

So if you're plumbed with 5", you'd need a short transition to 8" and you'd stick with a 5" vortex finder/outlet.

The transition from 5" to 8" could be fairly short and tapered.

I'm not sure when I'll have a chance to do more testing.  Right now I'm pondering how to make some of the parts from off-the-shelf components.

[retired2]

So if you're plumbed with 5", you'd need a short transition to 8" and you'd stick with a 5" vortex finder/outlet.

The transition from 5" to 8" could be fairly short and tapered.

I'm not sure when I'll have a chance to do more testing.  Right now I'm pondering how to make some of the parts from off-the-shelf components.

Oh, that might be possible for me to try without ripping out much plumbing, but I just don't have much time right now.  Haven't even had a chance to install the Wynn cartridge filter yet. 

[phil (admin)]

Yep, join the club.  I don't know how I can simultaneously be so busy yet getting nothing done!  I think I'm working on all the wrong things.

[DennisCA]

Ditto here. Well at least I made a table...

[alan m]

very interesting idea.

I don't think it will work with a pipe that small.
I think you would end up with a clog

I will try this for my self soon and see.


im thinking that if you had the main line (say 4") in and out 
then a 4" -6" reducer  . then  short length of 6"  pipe . the dust will go between the 6" and 4".
then put a 6" to 10" reducer and a 10" T. then reduce back to the 4"
hopefully the 2" gap around the 6" pipe will be enough to allow the dust to freely fall down the T and into the barrel

[alan m]

i got a few hours today in the shop.
I tried this.

I got a great deal on some 8" dc pipe and fittings, the type that clips together .
this is great for this type of brain storming . you can swap bits around easily and indefinitely

my main dc extractor is not connected in my ne shop yet so I tried this with my 4" record dx4000 . its more like a shop vac than a chip extractor

I got an 8" y with a 6" branch, reduced the end down to 4"
I got a blank cap and drilled a 4" hole in it and put a short pipe in it
I extended the pipe until it was inline with the start of the branch
the branch Is going towards the inlet side so that any dust  goes down the pipe

I didn't empty the dc so I couldn't exactly check everything

I got a bucket of chip and dust  (roughly 50:50)

I slowly fed it into the a 3 foot length of flexible ducting I had ( I found having a pipe before the separator worked better than just feeding it straight)
I fed it painfully slow

I worked out that about half the mixture bypassed the separator
probably 3/4 of the chips and 1/4 finer dust were separated

I will upload a pic or 2 tomorrow when I get home

overall it was a success . my gut tells me that it is more suited to chip separation rather than fine separation
I think you could hit 80-90% separation on larger dust but I feel you would be lucky to see 25% for fines

there is a lot of potential in this idea but it will need a lot of fine tuning.



I rearranged it a bit later trying to improve it and got almost total bypass.

[retired2]

i got a few hours today in the shop.
I tried this.

I got a great deal on some 8" dc pipe and fittings, the type that clips together .
this is great for this type of brain storming . you can swap bits around easily and indefinitely

my main dc extractor is not connected in my ne shop yet so I tried this with my 4" record dx4000 . its more like a shop vac than a chip extractor

I got an 8" y with a 6" branch, reduced the end down to 4"
I got a blank cap and drilled a 4" hole in it and put a short pipe in it
I extended the pipe until it was inline with the start of the branch
the branch Is going towards the inlet side so that any dust  goes down the pipe

I didn't empty the dc so I couldn't exactly check everything

I got a bucket of chip and dust  (roughly 50:50)

I slowly fed it into the a 3 foot length of flexible ducting I had ( I found having a pipe before the separator worked better than just feeding it straight)
I fed it painfully slow

I worked out that about half the mixture bypassed the separator
probably 3/4 of the chips and 1/4 finer dust were separated

I will upload a pic or 2 tomorrow when I get home

overall it was a success . my gut tells me that it is more suited to chip separation rather than fine separation
I think you could hit 80-90% separation on larger dust but I feel you would be lucky to see 25% for fines

there is a lot of potential in this idea but it will need a lot of fine tuning.



I rearranged it a bit later trying to improve it and got almost total bypass.

Sure wish I had the time to jump in and help with this new concept from Phil.  It is really intriguing and what attracts me most is Phil's comment about the lower pressure drop.  I would gladly trade some fines by-pass for lower line loss.

[phil (admin)]

I've started accumulating some parts for more experiments on my end.

I have a couple of ideas for maximizing fines separation but need to get my test rig built.

[alan m]

I think to fine tune this idea you really need  clear sides.

one thing I noiticed is that you need a long straight pipe before the separator
if you feed straight into it there is no time for the dust to go to the outside

there is no centripetal force helping put the dust to the outside

[alan m]

i got a few hours today in the shop.
I tried this.

I got a great deal on some 8" dc pipe and fittings, the type that clips together .
this is great for this type of brain storming . you can swap bits around easily and indefinitely

my main dc extractor is not connected in my ne shop yet so I tried this with my 4" record dx4000 . its more like a shop vac than a chip extractor

I got an 8" y with a 6" branch, reduced the end down to 4"
I got a blank cap and drilled a 4" hole in it and put a short pipe in it
I extended the pipe until it was inline with the start of the branch
the branch Is going towards the inlet side so that any dust  goes down the pipe

I didn't empty the dc so I couldn't exactly check everything

I got a bucket of chip and dust  (roughly 50:50)

I slowly fed it into the a 3 foot length of flexible ducting I had ( I found having a pipe before the separator worked better than just feeding it straight)
I fed it painfully slow

I worked out that about half the mixture bypassed the separator
probably 3/4 of the chips and 1/4 finer dust were separated

I will upload a pic or 2 tomorrow when I get home

overall it was a success . my gut tells me that it is more suited to chip separation rather than fine separation
I think you could hit 80-90% separation on larger dust but I feel you would be lucky to see 25% for fines

there is a lot of potential in this idea but it will need a lot of fine tuning.



I rearranged it a bit later trying to improve it and got almost total bypass.

Sure wish I had the time to jump in and help with this new concept from Phil.  It is really intriguing and what attracts me most is Phil's comment about the lower pressure drop.  I would gladly trade some fines by-pass for lower line loss.

I presume there is less pressure drop because the air stays straight and doesn't have to spin around like in a normal separator
the reason for putting the baffle separator before the dc is to stop the larger chips hitting the impeller
if this separated them out then we could put a baffle separator that is designed for fines and maybe increase the overall efficiency  of the system