Thien Baffle question

[jussi]

So I'm finally to the point that I'm absolutely sick of having to empty out the dust via annoying, and hard to remove, plastic bag on the DC. Let alone having to clean out the filter.

So I've decided to go with the time tested, and very popular, Thien baffle. I recently just got of those dust collector separator lids, similar to the one below and wanted to incorporate said baffle in the design. Phil's design however has the output port center of the container. The separator I got doesn't. Will that totally screw up the design?

http://www.amazon.com/gp/product/B00...pf_rd_i=507846

[phi1l]

I recently just got of those dust collector separator lids, similar to the one below and wanted to incorporate said baffle in the design. Phil's design however has the output port center of the container. The separator I got doesn't. Will that totally screw up the design?

ya, exit in the center is rather critical to the design.

If you have a large enough dust container, you might be able to get something that can approach the Thein baffle though. First you will need to add baffling that will direct the inlet air flow horizontally & tangentially to the side of the container. Second, you will need to construct an outlet that is in the center of the contianer, not off to the side, and below the inlet. But even then you will have to empty the container when it is about 1/2 full or less to prevent scouring of collected dust back into the air stream

[toolguy1000]

these generally work better:

http://www.woodcraft.com/Product/200...clone-Lid.aspx

there are a few threads/pics on phil's site that even show how this particular lid incorporates his baffle quite successfully. i have no experience with the lid you posted, so i can't offer any first hand advice concerning it.

[pelligrini]

Be careful in your choice of cans, and you might want to make a relief hole/valve.

I killed a can in less than a minute using a pretty strong Rigid vac and the woodcraft lid.
http://www.bt3central.com/showthread.php?t=43345

[dbhost]

Yes, that will not work with Phil's baffle... You really ought to read up on Phil's web site, just Google Thien Cyclone, and you will get there... His thought process on the port location makes complete sense... The only pre made lids I know of that are still available with that port layout are the lids from Lee Valley.

FWIW, My lid on my DC Thien is simply the plastic lid from the drum, 2 holes cut into it with my jigsaw sized for the 4" ports (ports installed with clear silicone adhesive caulk).

Some guys fuss about picking up a fully loaded 55 gallon drum to empty it. I do it a lot, and it doesn't bother me at all, and I have a bad back... If you decide to go with a 55 gallon drum, go with an open head plastic drum, and make sure you get the lid, and locking ring with it. No air leaks in mine for sure, and the separation works great! I did upsize my drop slot to 1.5" instead of 1.25" due to some clogging issues with full width planer shavings bypassing the baffle and getting into the DC, not a single problem since then...

[master53yoda]

Two things to bear in mind if you are using a vac for the power source you need to use some kind of pressure relief valve or you WILL collapse the garbage can at some point. Vacums develop 2 to 3 times higher negative pressure then a DC does, the only way to get a DC to generate that kind of suction pressure is to put 2 or more in series. In the same way you can parallel two or more and increase the volume and the size of the piping system.

The tops that you buy like the one shown separate based on particulate entering velocity. This is not the same design criteria as the Thien separator is. The Thein baffle works off of the same criteria as a cyclone, cyclones have the outlet air stream in the center of the chamber.

What the Thein baffle accomplishes is accomplished by the funnel shaped portion of a cyclone and the fact that the cyclone does not store the separated materials but drops them into another container.

the Thein baffles shortens vertical distance required to separate the particulate and isolates the stored material from the separation process in less physical distance then the cyclones can. In time i think the Thien baffle will replace many of the cyclones in use due to the less expense and room requirement to accomplish the same thing.


The use of elbows or side inlet and center outlet is part of the design of a Thein baffle and cannot be separated. I have seen projects where the builder failed to understand that it is a complete design of the top 6" or so of the device and they don't understand why it doesn't work right when they mess with the air flow patterns by moving around the inlet and outlet.

The only limitation is that the gap between the baffle and the container wall does effect the size of particulate that it will separate. Anything larger then the gap won't separate, if the gap is made to large then the efficiency of separating the fines is reduced. Also it needs sufficient CFM as does a cyclone to work properly.

I think part of the confusion is that we all refer to it as a Thien "Baffle" which is only partially correct, it is a Then "SEPARATOR" and we need to stay with the complete design and only modify size for the air flow and particulate being separated.

[toolguy1000]

jussi...here is a link to the thien site:

http://www.cgallery.com/jpthien/cy.htm

it has threads dealing with just about everything you need to know concerning separators and how phil's baffle makes them work very well. there are threads on different tops, most of which will work but, according to phil, are probably not worth the cost since you can make one cheaper and better, and there is even a thread on the design and construction of a pressure relief valve to address ths cruched trash can noted previously by pelligrini. HTH.

[smorris]

Not to go off in the weeds, but I have a question about using the seperator. When I mounted mine I also installed a neotral vane, reading some of those threads advise against that. It seems to work well but would removing the vane cut down the turbulance and help keep my filter clean longer?

[cgallery]

Not to go off in the weeds, but I have a question about using the seperator. When I mounted mine I also installed a neotral vane, reading some of those threads advise against that. It seems to work well but would removing the vane cut down the turbulance and help keep my filter clean longer?

I used to think it would. Reports from some users contradict my own research.

Short answer: It depends.

[phi1l]

Not to go off in the weeds, but I have a question about using the seperator. When I mounted mine I also installed a neotral vane, reading some of those threads advise against that. It seems to work well but would removing the vane cut down the turbulance and help keep my filter clean longer?

a neutral vane may be helpful, depending on the configuration of the piping going into the separator. IF there is a very tight bend right at the entrance to the separator, that bend will direct the air an odd angle going into separator, possibly reducing efficiency. The neutral vane will straighten out the air flow. So it really depends on the piping configuration, whether a neutral vane will be useful.

[smorris]

I was puttering about in the shop today after abusing my back unloading a bunch of cherry. I opened up the DC and cut out the neutral vane. 2 immediate observations, it got a little quieter and I no longer have material collecting on top of the baffle or getting into the upper bag. I'd say in my case removing the vane helped.