J. Phil Thien's Projects

With that setup you don't need a lid - use the tank in place of the lid, sealed, of course, to the can below, totem style. Put a hole in the bottom of the vac, insert a short pipe in the vac tank to keep the chips from falling back in the lower can, and use a side attached inlet hose on the can with the separator as usual. And if you need to use the vac stand-alone you can cap the hole in the bottom.

One problem I see with it is the outlet is off center and so closer to the swirling chips which provides a better opportunity to allow chips to leave the system. A mod I would make is to cap the bottom of the outlet and cut a wide slot toward the lid center so that the air leaving is coming from a spot closer to the vortex center.

That said, I don't have a good picture of what the bottom of that lid looks like so am assuming it is simply a spigot, or perhaps just a hole in the lid with no lower extension at all. If the latter then an elbow aimed at the lid center may improve things. In any event the object is to have the outlet air come from the vortex center.

It's a bit off topic but still worth knowing.

http://www.snopes.com/science/coriolis.asp

I used a strip of foam 1"x3/4" that has stickyback tape on it. It self-seals from the lower pressure in the container when the vacuum is running. I google'd fiber drums and found several sites that sell drums that have clamp-on lids that eliminates one of the weaknesses of using the galvanized trash can I have so will be going with that in the next version.

Bad form to reply to yourself! but, I've just constructed a stacked vacuum and Thien Lid and it works great. Here's a set of images that hopefully explain my version. Particle separation is beyond belief.

http://thevirtualbarandgrill.com/machinery/ThienLid/

I found this stacked option interesting and thought about it for a bit. It seems logical to eliminate the external hose and elbows entirely and simply penetrate the bottom of the tank of the vacuum and feed it directly from the output port of the Thien lid. There's no reason the existing inlet port on the vacuum must be used as the entire tank runs at a reduced pressure. This design requires capping the vacuum's existing inlet. This allows the vacuum to remain upright, provides a short sealed path from the lid below, and a strong structure.

In addition, rather than the lid having the inlet port built in it is possible to attach the inlet hose tangentially to the side of the lower chamber such that the inlet is located between the lid and the separator disk. This eliminates the inlet elbow from inside the lid and should also make a clean vortex.

The connecting hose between the lid and the vacuum tank should continue up into the tank such that the opening is above the expected soil level - a flex hose inside the tank with a relaxed curve to allow a horizontal outflow is easily accomplished.

I've most of the bits to try this with my own setup. With the tangential inlet, cleaning the collection tank should be no different than existing builds except the vacuum comes off with the lid as the inlet host does not project into the collector tank. Forgive the noise if this has already been tried.