An inline separator idea

[golfeng]

This type of technique has been used for well over 50 years in some chemical processes. It is called turbannular stripping. It is well documented in patents. Normally it is used to remove liquid and solid particles from a liquid/solid/vapor mixture. Provided the velocity if the mixture is high enough at the inlet of the turbannular stripper the liquid/solid phase will stick to the wall of the tube and the vapor will retain it's high velocity. The turbannular stripper then feeds a cyclone separator, the liquid/solid phase stays together and goes out the bottom while the vapor phase goes out the top of the cyclone. The geometry of the tube is critical with the diameter small enough to keep velocity high enough and the length of the tube sufficient to establish and maintain a donut of liquid/solid on the wall before the entrance to the cyclone.

[BernardNaish]

Now that is interesting! I love it when we re-discover something when we come at it from a different direction.

Are there any on line sources of information about this?

[golfeng]

See page 452  figure a


https://books.google.com/books?id=1W64gOffM7EC&pg=PA452&lpg=PA452&dq=turbannular+stripper&source=bl&ots=7W8Jf9sE9h&sig=wvWEqOuK0OEUfRE8YZKRyc8CUpM&hl=en&sa=X&ved=0CCMQ6AEwAmoVChMI8PK3k6-DyQIVxBseCh0AIQTk#v=onepage&q=turbannular%20stripper&f=false

The turbannular stripper is also capable of doing organic extraction when the vapor medium is something like steam. The steam will boil off a volatile material in the stripper and allow an easier separation of a water and organic mixture.

[BernardNaish]

Thank you. Bit above my pay grade but I will struggle through.

It occurs to me that if the inline separator can be developed to remove a significant quantity of the finer waste without wasting very much of the DC suck, then we could put one in front of a Thien top hat.

I think this may result in an overall increase in the removal of fines with the bonus of being able to increase the Thien slot width so deducing blockages there.

I am doing less and less machine work but this whole waste/dust collection theme fascinates me.

[nucww]

This is summary of my dust collector that I spoke of in an earlier response.  Most of the design and credit comes from the contributors of the topic:5", Rectangular Inlet, Bellmouth Outlet with Air Straightener, Top Hat Separator.
This is being used with a HF DC so the design was trying to minimize pressure drop to maximize flow.
Some of the significant differences are:
-  spiral chamber with the spiral starting ~6" before chamber entry.  The spiral lost ~2 1/4" per revolution.
-  a high narrow rectangular inlet (10"x2.25") so that entry dust is already close to the outer surface
-  Plexiglas on the top and formica for the spiral sides
-  Baffle slot was extended to ~320 degrees since the spiral design should minimize turbulent entrance.
-  a 3/4" MDF baffle with the slot edges tapered to ~1/4".
-  5" outlet pipe with a X flow straightener
-  a commercial bellmouth outlet pipe with the flat part of the rim cut off resulting in ~7.25" OD mouth for a 5" base pipe
-  flow diverters at the bottom of the wide mouth to divert the flow up rather than spinning around. Some CFD simulations show that vortex in the center is huge and is likely causing significant pressure losses. 
I had a anemometer to measure airspeed to test some of the differences.
With the standard HF setup, 10' HF flex pipe and a 4" to 5" transition, the airspeed at the surface of the 5" transition was 48 mph. (airspeed with a 4" pipe was off scale max of 67 mph)  With the same piping and with the dust separator installed, the speed was 45mph.  So this design only lost 3 mph. 
Installed a .5micron wynn filter, put the motor on top of the collector, patched some leaks in the impeller housing, and put a foam insulation strip between the bottom bag and the housing.  With the dust separator installed, the speed improved to 51mph with the same piping as the previous test.   So getting rid of the 5" flex pipe and adding the extra area of the wynn filter gained about 6 mph as noted by others on this web site and elsewhere giving me a net gain with the dust collector of ~3 mph .
I used hvac 5" ducts for the main line and all drops from the ceiling are 4" pipe.  I made my own wyes since the commerical ones were expensive and the cheaper hvac ones had the wrong end crimped.  The longest run of 5" was about 16'.  For all 90 degree turns, I used 2 elbows at 45 to make more gradual turns.  After installing the pipe I tested the longest run of 5" pipe and the speed was only 38 mph.  Taping all the joints made a huge difference.  The speed was now 54mph.  A gain of ~3 mph changing the 10' - 4" flex pipe with the metal duct.
I allowed a cup of flour to be sucked into the inlet to the collector and ~ 2/3 of it ended up in the trash can.  There was some visible in the chamber and the edges of the trash can.  Some made it to the bag after the impeller.
Attached is a picture that better shows what I am describing. Evidently, I can only send one of these at a time.

[nucww]

I agree. I'll copy it so it doesn't clutter this one.  This was the forth time I time to post it and I did not know why it was not working so I added it to an existing thread.  While doing this I got a message saying that I could only load one picture of this size at a time.

[Clark Savage Jr]

Trying to post an image. If the swirl created by the impeller is great enough [TPI] then perhaps you have enough of a vortex to cast particulate to the outside of the tube. So wondering if a 6" or so tube, long, with the fan entrance at the top per this setup may cause the particulate to first flow outside due to the elbow inlet, continue to swirl enough to rise and exit the slot cut into an outer tube and fall down to a container. If the container is airtight, then there is no pressure differential or flow and same as your Thien baffle, will cause separation. You may have simplified the Thien baffle as a pseudo reverse cyclone arrangement inside-out! It would be easy to support the tube lower than the exit, therefore nothing in the way to create any friction or other turbulence.

Just throwing it out there for you, could not sleep last night.

[Clark Savage Jr]

Just realized - not clear - the [intake] inner tube is 6" diameter minimum, the length is much greater in order to allow centrifuge separation.

Good night  :)

[Clark Savage Jr]

Well, you are making me crazy - I may have to build this. It would be SO simple.

A few more images, supports for the center intake tube, flange for the lower can, removable top hat to the fan.

Easy to check, easy if needed cleaned [can't actually see a reason anything would need to come apart]. I like it. I may just abandon my more complicated build and do this first. Thanks for the prod.

It should not require air straighteners because we would want the impeller to impart the vortex. Straighteners at the entrance - BEFORE the elbow may help in hoses or pie runs to curtail some circular flow losses, streamlining the flow to the device. Once past the elbow, particulate not thrown out from the elbow and now spinning vortex imparted by the impeller, would then be encouraged to the outer inner pipe wall and then thrown out at the NOW 360 degree slot with no re-entrainment to fall through the outer pipe wall to the bin! Could it be possible? The center of the vortex is somewhat negative, perhaps like the eye of a hurricane. So if the very light fines are not washed out, they may make it to the impeller and thus the filter. But it may work better than any other alternative?

Perhaps I am just too tired and will try to stay away until I sleep.

[Clark Savage Jr]

We know the effects of the bell-mouth, and how akin to a distorted bubble the air flows out between two opposed bell-mouths as two mirrored black holes if in a constant state [unit on and vacuum established]. So I am wondering if the spinning vortex of this may yield the separation I seek, allowing the dust to escape into the outer chamber, if not all, at least I am believing it would be a  very low loss first stage? I really think I need to try this. Maybe I have become not a bellmouth, but a blabbermouth due to the fact I have not slept today. Like all good things in life, I may just end up regretting it in the morning  :o Go ahead, trash me  :)

[bark-eater]

Just wondering if any one had any luck with this? I'm looking for a pre separator for planer shavings and had hopes for this design.