J. Phil Thien's Projects

Quote from: CharlieL on October 03, 2009, 10:04:59 AM
While air leaks are obviously not good, even after you do fix those leaks don't expect the seperator to get 100 percent of the dust, especially the fine stuff. Even the cyclones that are built for the masses don't get all the dust, especially the fine stuff. In my opinion, a seperator, and or a cyclone is designed to get the big stuff so the blower doesn't have to deal with it, and it cuts down on bag changes due to being full.

Yes, I understand this.  And I really appreciate the elegance of the Thien's design as I've tried to make my own cone shaped separators. My dust set up is totally home grown and I am (subjectively) seeing (actually feeing at the exhaust) some issues in air flow reduction due to clogged filters (about 800 sq inches of higher end furnace filters - I don't remember the MERV (spelling?) of the filters).  I haven't settled on the overall design so I haven't had a chance to clean everything out and install new filters to see if "tuning" my Thien separator will make a significant difference.

Right now I have a huge cavity in front of 800 sq inches of flat filters.  I was going to put my separator in there, but the dimensions of the "let's quickly put a Thien garbage can separator together to see if it really works" exceeded that of the cavity.  The cavity is about 2x3x4 feet.  Any suggestions would be appreciated (i.e. put a second smaller Thien separator in there, two tandem Thien separators in the cavity and get rid of the big one, where to get a 2x2 foot garbage can, ect...)

-thanks

Quote from: dbhost on September 11, 2009, 03:17:48 PM
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I am a bit concerned you are only removing 75% of the dust though.... Is it just not getting picked up and ending up on the floor / on your saw (that would be a dust hood problem, or insufficient CFM etc...) or is it ending up in the filter / filter bag? (or whatever you are using if not using an off the shelf single stage DC).
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My set up is custom all the way and is built around a old AC 110 volt powered GE furnace "squirrel cage" fan.  I wired it up for both cooling and heating speeds. So I think the fan's CFM is not an issue.  I am seeing dust on the 2 20x20 high efficiency filters and on the floor of the (way over sized) filter chamber (which is about 16 cubic feet).  What I should do is tune up my Thien separator.  I used the original can's latching lid which now has to sit proud of the can because of the added wood.  Some weather stripping run around the inside rim should fix that.  Also, the can has drain holes I only taped over.  I suspect they are leaking and should be silicon sealed.  Last, I have to find a better way to mount the 4 inch S&D pipes.  They are currently fiction fitted and are "kind-of" staying put. After the tune up, I'll do a thorough cleaning of the system (which is quite large - my bad) so as to easily identify any new dust collected past the Thien separator.  Maybe I'll get better results then.

Quote from: dbhost on September 11, 2009, 03:17:48 PM
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Unless I overrun my dust bin, I generally get about 1/2 cup of fine dust up into the filter / vac on my shop vac based setup for every 10 gallons of fine dust and mixed material I pick up.

Wow - really?  I definitely need to tune my system up!

BTW - where is most if not all your dust from?  I have been cutting plywood which tends to make fine dust.  I was thinking once I get my router table running that would produce larger dust and chips which may be easier to separate (i.e. I am expecting the Thien separator to work really well with the router dust).

Quote from: dbhost on September 11, 2009, 01:06:50 PM
You are close to right.
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The elbow in question empties out at the start of the solid part, not the drop slot, or aperature as you called it, so that they loaded air is slightly deflected away from the shavings / dust below.
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Good thing you took your time as it gave me a chance to finish up my dust collector.

My inlet elbow starts at the beginning of the solid part (where the bottom plate meats the side of the container) but the opening is actually about 1/3 the way past that.  It looks just like the picture except I am using 4 inch S&D pipe and a 20" (approx diameter at top)  recycling can.

I believe it is doing a fine job - but wished it was trapping more of the fine dust.

I would say my Thien separator is removing about 75% to 80% of the saw dust generated from my table saw. The reset, I think, is ending up either on the floor of the filter box (which is about 4 x 2 x 2 feet - a really massive space) or on the filters them selves.   But this fine dust is really hard to quantify let alone collect.  (The generous space in the filter box was for a set of mini cyclone filters that I never implemented - as that design got more and more complex.)

As for the fine dust collection problem - I have noticed patches of fine dust clinging on the top of the bottom Thien plate.  I think I have see the same on pictures here of other people's Thien separators.  There seams to be a space of low turbulence on the way to the exhaust or outlet connection.  Is there a way to exploit this and remove the fine dust?

I was thinking of cutting yet another circle about 6" wide (in my case) in the bottom Thien plate and raising it about an inch.  This might give the fine dust travelling to the exhaust an opportunity to drop into the collection bucket.  But I think all this will do is create turbulence in the lower part of the bucket doing more harm than good.  Perhaps if this second opening could be isolated (a bucket with in a bucket) there would be no chance of additional turbulence.  Of course, my Thien design just got all that much more complex.  If I have any success with this idea I'll try to post a follow up.

Sorry for my dribble...  Is there a better thread to talk about modifications?  Or are you all ok w/talking about it here?

-thanks everyone for working and putting thought into this project.

Quote from: dbhost on June 30, 2009, 01:18:12 PM
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In regards to #2. YES the orientation of the baffle to the inlet bend is important, and that is NOT an optical illusion. You want the solid part just starting as the air comes out of the inlet so it can ride around a bit before stuff drops into the can. I have seen (read I messed up and oriented it wrong) this done backwards, and scrubbing becomes a very real problem very fast...

I am confused by some of the pictures as well.  However I think that rfcomm2k's comment is based on a picture where the camera is not lined up with the center of the baffle AND lid.  So, it appears that the center of the baffle is not at the center of the lid OR the trash can.  This would result in an aperture (hole where the dust falls to the bottom of the trash can) that would look like 2 half crescents and some sort of hard to describe arc.  Bizarre.  This is most likely incorrect.

I think the center of the lid AND the baffle AND the trash can are all the same.  I think the aperture looks like a ~1 inch 240 arc.  The arc appears to start about 200 degrees after the inlet pipe and ends about 40 degrees before the inlet pipe.

Do I have that right?

-thanks everyone for contributing!