J. Phil Thien's Projects

Dunno about performance...but probably. the other thing that happens when you stick the pipe into the cyclone, you make "traps" where junk collects but doesn't drop into the collection bin.

Guy, in my TopHat application, I used PVC, because it fits the hose from my ShopVac. I formed the inner circumference of the separator with some aluminum flashing I had laying around, cut a hole for the PVC, then recut both the aluminum AND PVC a couple of times till it fit. In use, there is a little residue that collects around the edge of the PVC where it penetrates the inner circumference of the TopHat, but it's not a big deal. More problematic is the curls of wood from hand planing, that want to wrap around the 1/4" threaded rod I use to support the baffle.

Nevertheless, it works, far better than I had ever imagined such a seat-of-the-pants assembly. I doubt I would use it for a permanent installation, with duct work, blast gates, and so forth. I have a "new and improved" design in mind that will cost considerably more in parts and labor for that. But for now, my ShopVac / TopHat solution is superb for vacuuming up the detritus from my (rather successful) attempts to reduce large and expensive pieces of wood into small and mostly ho-hum works of art.

Ain't wood working fun?

PS: if you do a search on my username, you will surely find photos of my design.

I assume the Rikon impeller promises significant performance gains over the one that comes with the HF unit.  Otherwise, isn't this a helluva lot of work to do?

I built my first Thien separator (a top hat) using a hand-held jig saw, a hand-held belt sander and a battery powered drill-driver. The beauty of the design is that it is so darned effective and yet so stupid simple to build.

Phil is right that a shop vac will collapse a metal garbage can. I reinforced mine by screwing on some external ribs: two rings of plywood at third points, vertically. I didn't seal the holes made by the screws, and the system works just fine now. I.e.: it gets all the big chunks, still, and 90% of the fines, but the can doesn't collapse. My guess is you probably don't need all the punctures I wound up with, but some relief in case of a plug isn't a bad idea.

Somewhere on this forum, in a post under my name, are pics of the "repaired" metal can. I failed to take pics of it immediately after the collapse, but if you find the repaired pic, you can see the "wrinkles" left over after I pushed the can back into shape.

My solution was to add plywood rings at the 1/3 points, vertically, outside the can (actually, two half rings at each location). I drilled through the can and using some #8x1/2" pan head screws, attached the can to the rings. I didn't bother sealing the holes--there is plenty of suction and the top-hat separator still removes 90%+ of everything I send through it.

Just be aware, that a shop vac has enough static pressure to collapse an unreinforced 30-gallon metal garbage can. You are welcome to ask me how I know this.   :D

When you think about it, a Thien separator is pretty much a centrifuge: a mixture of fluid and particles (air and sawdust) is flung around a circular chamber and the big gunk falls out. Seems to me that if you mixed your soil with water and flung it around (vigorously!) inside a circular chamber that was composed of some sort of screen, the heavier stuff would drop out, as would most of lighter fluff and you'd wind up with mud on the outside. Of course, to collect all that, you'd want a second chamber, arranged annularly to the first and some way to carry off the slurry.

Gold miners have been doing something along these lines for centuries.

Laundry dryer vents use a back-draft damper--that opens when air blows out, but is closed otherwise.
Years ago, my shop was the location of our laundry system, and the dryer vent through-the-wall thimble, with its back-draft damper still remains. The only "vermin" that make their way into the shop through it are spiders. I am reminded it's there when I open or shut an outside door suddenly, as the damper flaps momentarily to equalize the changes in pressure. Mine is 4" diameter--the standard dryer duct size--but I bet if you went to your local HVAC company, you'd be able to get one in any size you want.

Others may have a better handle on this, but it seems to me that any time you increase the distance in a tube (hose or otherwise) for the air to travel, you lose something. But as the Kirby is a vacuum cleaner (high static pressure), this may not be as much of a problem as is the overall volume of air being moved. What's the diameter of that hose? <5cm?

I think, if you're after a bell-mouth inlet, you have the curvature going in the wrong direction. The idea of a bell-mouth inlet is to remove turbulence at the opening of the inlet. It should look like the reverse of a trumpet bell. In a trumpet, the sound is spread outward by following the curve of the horn's tube from narrow to wide in a smooth transition.

With your set-up, you haven't smoothed anything out, especially; just moved the narrow portion of the tube into a mini-cavity, which seems to me will create more turbulence, not less.

What you describe is pretty much the tophat solution for the HF DC. I am using a section of 5" snap-lock to close couple my tophat to the blower. Of course, this means I need to either move the tophat AND the blower up and down to empty the barrel ... OR, my solution, to move the barrel up and down under the thing. That might not work well if you intend to use the cart supplied by HF.

Ron, that is a super cool idea.

I'm gonna steal it.  8)

Okay guys, I'll post the thing. All the usual disclaimers apply. But be patient--I'm in the middle of another project, so it may be a day or so.

jgt: the SketchUp feature you mention is in View: Component Edit: Hide Rest of Model and/or Hide Similar Components

Very useful feature.

jgt:
I changed from 6"? to 5"? because the dust collector I will use, the so-called 2 HP unit from Harbor Freight, just can't move enough air to be effective in 6"? ducts.  And there is too much friction loss in 4"? ducts.

My SketchUp model is essentially the one you found earlier, but I have edited the model for 5" duct as I explained.  I did not keep the model for 6"? duct. Sorry. Doug28704 has a pretty decent model too. And of course, so does retired2. Both of these gentlemen have the air flow in the separator moving counter clockwise (when viewed from above) to match that of the blower fan. My unit, because of space considerations, will rotate clockwise. I will install some sort of "air straightener" similar retired2's solution, as it seems the optimum air flow into the impeller is to not rotate at all.

Now if you are interested, I have fabricated two long-sweep elbows using 6"? S&D that I will not use now that I'm going with 5"? metal duct. One is 90?, the other is 45?.  Radius to diameter is 1:3.  :D