J. Phil Thien's Projects

I thought that if the separator was before the blower, that the filters have to be after it.

I think the problem is that CFD is time consuming, too, and there are errors involved.  You can find studies comparing CFD predictions to real-world (line wind-tunnel) tests.  Pretty interesting stuff.  Can take months of work to get close, and the CFD results improve because of feedback learned from empirical tests.

I suppose if CFD sims were accurate, outfits like Oneida and ClearVue would be beating one another over the head with it.

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.

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.

Quote from: clydeone on September 09, 2015, 12:28:40 PM
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.

Quote from: sploo on September 09, 2015, 01:51:54 AM
It sounds to me like you've got some really good ideas but are doing a lot of empirical testing. Would it be worth trying to find a friendly fluid flow expert with access to the relevant simulation software? It occurs to me that you could probably move things forward quite quickly with visualisation of the actual flows. I'm making significant assumptions that you don't already have that, given I don't know your background, I'll admit.

LOL, there is a shortage of friendly experts with access to simulation software.

Quote from: sploo on September 08, 2015, 04:18:12 PM

Quote from: phil (admin) on September 08, 2015, 03:52:03 PM
I'm including a pic of my "inline separator."  It has about the lowest pressure drop you can achieve.

Very clever. For a low pressure system such as an impeller based extractor, would the smaller pipe not kill the airflow though? I understand that low pressure air behaves more like water - i.e. incompressible - so forcing it through a smaller gap doesn't really work (unlike with a high pressure shop vac, which works fine).

You're correct.  The key would be a vortex finder that matches the mains, and an outer pipe that is upsized for a length.  So if your mains are 6", the outer pipe would be 10" for at least some length.  I don't know what that length is, you obviously don't want settling before the wye.

Obviously need a lot more testing.

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.

Quote from: sploo on September 07, 2015, 06:38:53 AM
I would be interested in pressure loss data though, as I'm less worried about separation efficiency (venting outside, so mostly interested in just separating the visible dust - some smaller particles making it through don't worry me). So, I'd prefer low pressure loss and average separation to high pressure loss and really good separation.

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

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 all 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 puts 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.

One other downside would be lower separation rates.  It works way better than anyone to which I've demonstrated it would believe, though.

There are numerous advantages, though.  Takes up almost no space and limited ceiling height isn't a problem.  Very little pressure drop.  Not too difficult to build even in larger sizes.

I need more time to experiment with it.

Well if you've ever seen the final filter stage on a 10-HP cyclone, now imagine putting that INTO the top hat.

I'm afraid it wouldn't be practical.

It would be doable on shop-vac based systems but not a 10-HP blower-based system.

Quote from: tomservo on September 05, 2015, 05:31:18 PM
I'd say that if you have room for a cyclone, just do that, the pressure loss is much lower. Have you seen the newer oneida cyclones? they look like great value to me.

In other news, my separator is done enough for some testing.. I made the fiberglass inlet and the spray foam attachment is drying now. I'm hoping to get a felt bag for the outlet from kijiji tomorrow.

Do we know pressure loss is much less?

The pressure loss should be somewhat proportional to the D of the separator.  Some of those newer cyclones are pretty tiny.

Mind you, I'm not saying you're wrong and I'm not trying to limit discussion, this is a free and wide-open forum.  And someone may have posted evidence that the pressure drop is lower somewhere (even here).

Just asking.

I've been tempted to try it w/ my shop-vac based system but prefer having the bag in the shop vac act as the first line of defense.  No matter how good a separator you have, some always gets by and the vac bag (in my case) catches almost all of it and the final filter stays more-or-less clean.

It's alive!!!

Nice work, what a monster!

Oh yeah good point.

Well I can't wait to hear how this one works.

I have high hopes.

Have u balanced it yet?