New build....Here we go....

[Rudy81]

Another busy day today with this project.  I got 95% of my materials delivered.  Unfortunately, I let the folks at Penn State talk me out of the bellmouth I had originally ordered and they sent me a bellmouth designed for one of their products.  Sadly, what they sent will not work with this application, so that has set me back at least a week.

While I wait, I decided to work on a plenum to direct the exhaust air.  I wanted to be able to 'see' if there is anything getting past the Thien separator and also be able to remove any such items from the plenum.  So, I came up with a box that incorporates a Plexiglas window.  The section with the window is easy to remove in case I ever need to clean out the box.  Pictures below.  BTW, the plenum has three large openings to the outside that are covered with screened louvers. 

I am planning on using a couple of rivets to hold the major pipe components.  Based on various comments, I think that might be better than screws.

I picked up all the pipe from HD online.  Most is 26 gauge, and the wyes are reverse flow, so that makes life easier.  Can't imagine I could have done this any cheaper with PVC.

[tvman44]

What is the diameter of the metal tubing you got from HD?

[Rudy81]

I ordered all 6" for my main line.  I have a few 5" pieces I picked up locally at HD for the DC exhaust.

[tvman44]

5" is what I am interested in, I want to use some 5" to exhaust my DC outside.  Right now I am using some 4" flex to exhaust outside. :)

[Rudy81]

tvman44, I too used 5" for my exhaust setup.  I found everything I needed at HD and Lowes.  HD was the only place that had the 5 foot sections of 5".  Otherwise, both stores had 5" pieces. 

[Rudy81]

Just finished the installation of the bellmouth. I have not been able to test the complete system today since I'm allowing the final bit of sealer to cure before adding the last bit of aluminum tape to the intake. I am really hoping this works.  It has been a lot of work which included running 6" pipe all over the shop. 

The bellmouth fit perfectly the crimped end of a pipe, which also holds the air straightener. 

[Rudy81]

I routed a hole large enough to allow the bellmouth to drop into the Thien enclosure, then made a disk to fit that hole and another larger disk to seal the top.  I used foam tape on the larger disk to keep a tight seal on the top of the enclosure.  BTW, the 6" bellmouth has a bell diameter of 12 1/8".

You might note that the DC exhaust pipe is different than I originally set up.  I didn't like that pipe having a tight 90 bend. I figured it could cause the DC to work harder than it needs to due to back pressure.  Not sure if that is correct or not, but it was worth smoothing out the flow a bit.

Tomorrow I will fire this thing up and see if it works.

[Rudy81]

Finally!  Got a chance to test the project out and so far it seems to be a total success.  I ran various handfuls of dust, mostly MDF and smaller wood shavings.  Although I have not checked for leaks, the system seems to have plenty of power.  The following video was made using a 10' long, 6" plastic pipe connected to about 4' of metal pipe (total distance from the inlet).  I did not notice any visible dust being exhausted and when the system was shut down there was nothing left in the baffle.

Thanks again to Phil and those who posted their ideas on the subject.

http://www.youtube.com/watch?v=LHExpJoeu3E

[phil (admin)]

Looks awesome Rudy!  I look forward to reports after some extended use.

[Rudy81]

Phil, Thank you again for all your work.  I will report after I actually get to use it.  I'm still running pipe and setting up effective collection at each machine.

One thing I noticed when comparing youtube videos of various builds is that the taller the area above the baffle, the shallower the slope of the 'swirl' on its way to the Thien slot. The shorter containers have a much steeper slope. Is this a function of the inlet, the height of the container, or some other design feature?

Thus far, I am very impressed with the efficiency of dust separation. 

[phil (admin)]

One thing I noticed when comparing youtube videos of various builds is that the taller the area above the baffle, the shallower the slope of the 'swirl' on its way to the Thien slot. The shorter containers have a much steeper slope. Is this a function of the inlet, the height of the container, or some other design feature?

That would be related to the volume above the baffle, the surface area of the outside wall, and the location of the inlet.

[Rudy81]

Finally got a chance to work on a project actually using this system.  The Jet 1100 DC together with the Thien baffle works perfectly.  No problems at all.  Cut plenty of MDF on the TS today and did not even have to do any clean up when I was done....just amazing. 

I did add a blade guard with dust collection connected to my shop vac.  Which is now also vented to the outside.

[JeffQ]

Rudy - I'm about to build my second Thien baffle in a top hat design not far off of what I have seen you do in this post. I'm trying to squeeze as much as I can out of a relatively marginal Grizzly 2hp blower. It seems there is a worthwhile separation advantage in using the taller chamber as you have and using a round to rectangular transition at the intake to the separation chamber.

Since I have all of my main runs in 6" S&D PVC pipe, I am thinking of trying to heat form the round to rectangular transition right from the 6" S&D to allow a little smoother transition and easier matching to the main duct pipe... but maybe it won't be worth the time spent forming the transition. Your sheet metal round to rectangular transition certainly seemed to make that part of the fabrication pretty simple. Now that you have a little experience running your version of a Thien separator with all of your ducting in place - is there anything you would have done differently with your build?

[Rudy81]

JeffQ,

I have used my build for about two or three days' worth of work and thus far have no complaints.  I am getting plenty of CFM draw from my modest Jet DC.  I can only credit a successful build to all the various posts and ideas others have come mentioned.  As you can  see, my build was a compilation of the best ideas I have found on the site.

I highly recommend the round to rectangular metal piece I used.  Works great and it is just to easy to install to go to the trouble of trying to hammer one out.  I would suspect you could easily adapt one to your ducting. 

I am still surprised at the effectiveness of the baffle I built.  If anything is getting past the baffle, it is not visible.....although I vent outside and don't spend too much time monitoring any output while working.  When I tested the system, nothing was getting past the baffle that I could see.

I hope this helps.

[Harnell]

I'm planning on a very similar design but have a concern about rotating the motor/impeller assembly from horizontal to vertical.  This will place different loads on the motor/impeller bearings.  Is there any data/information on this?  Is it a potential issue?  If I don't rotate the motor/fan I would have a 90 deg. elbow between the separator and impeller.  Does adding an elbow here add enough restriction to be concerned about?  I have a DC-1200 which is borderline if I want to keep airflow speeds high enough to effectively remove the fines from my tools.