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Thien baffle huge air loss

5K views 14 replies 9 participants last post by  jgt1942 
#1 · (Edited by Moderator)
Hello folks,
I have a question for you today. I've built one of these thien baffle for my King KC-3105C dust collector.
I've installed a homemade 6" to 4" reducer on the input and I have a huge loss of vacuum.
The garbage can and the intake of the motor have a snug fit to the baffle.
Please help, I will upload pictures later. Thanks.
 
#5 ·
I'm no expert but have experienced loss by adding a Thein separator. However, I also no longer experience big chips or debris hitting the impeller. While I truly miss the loss of suction, the added life of the impeller makes me think the positives out-weigh the negatives so far.
 
#6 · (Edited by Moderator)
By default, you will have "some" loss with a Thein baffle. It's the physical science of airflow in a chamber. But "huge" loss? Something else is amiss. As mentioned above, check for leaks. The 4"-6" restriction looks abrupt instead of gentle causing turbulence. I see no vertical chimney pipe from the chamber to your motor housing? I know that is critical in regards to the height of said pipe (my pipe is probably…3"-4" above baffle plate), else you introduce even more air turbulence.
The air gap sealing between garbage can and baffle structure is not critical.

Use the motor & baffle with a good amount of saw dust you have laying around and watch the intake & circulation pattern to see what's up. DO not use while operating machinery because you have to take eyes off the machine to watch the baffle chamber: not a good idea ;)

Gas Laptop Cylinder Fixture Engineering
 

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#7 ·
Thanks a lot for your replies. I will try to add some chimney between the impeller and the baffle.
The inside transition of the 6 to 4 plywood reducer is smooth, not as abrupt as it looks outside but
when I put my hand in it, I can feel turbulences.
I have just read that the slot should be flush with the inside of theplexiglass to allow the chips to fall,
which is not my case.
I will buy an anemometer to get some measurements.

Thanks again for your support.
 
#8 ·
I assume you mean your slot is 1/2" or 1" away from the plexiglass. The only downside of that would be the heavier debris will hug the plexiglass while lighter particles towards the center of the vortex. Unsure if that affects efficiency of CFM or just more debris flying around the chamber since can not escape so easily. My slot is butt up agains the plexiglass. And is 16" high.
Wood Floor Plumbing fixture Flooring Hardwood


Tis like a Christmas snow globe…. fun to watch :) Did you test your airstream with a handful of saw dust to see how the vortex handles things? Here was my test:

View on YouTube
 

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#9 ·
I have a Grizzly G1029Z2 2 HP Dust Collector that I converted to use the Thien baffle and I'm SUPER pleased with the performance. I used a 20 gal Brute only because I goofed and did not allow enough room for the 32 gal Brute. I assume that you cut a grove in the bottom of the Thien for the garbage can? In my grove I inserted a door insulation strip, this gives me a near air tight seal. There is no difference I could detect in my vacuum between the original setup and the Thien setup.

As I built the unit anywhere two materials met I either glued or sealed the connection. I see you have four screws holding the air intake on to the Thien did you seal all joints? When you installed the Plexiglas did you set the edge of the Plexiglas in a bead of caulk? When you attached the ends of the Plexiglas to the Thien did you put caulk between the Plexiglas and the vertical support?

I suspect that you have several leaks in the assembly of the Thien. BTW the Thien is just under 97% efficiency.

Have you posted in the Thien forum?
 
#10 ·
Since you have a king dust collector, I am going to guess you are in Canada….

Pop in to HD (or a similar place) and get a smoke pencil to see if you can find air leaks https://www.homedepot.ca/en/home/p.draft-detector.1000546294.html (I need to do this myself)

As well, going with 4" pipe, you will not get more than about 350CFM. That transition right at the collector, no matter how smooth, is reducing your airflow a lot. It would be much better to go with a larger pipe (you will get nearly 2x the airflow in 6" pipe vs 4" pipe)
 
#12 ·
jgt1942, and bbain32. Good idea, I will try with insence stick to detect leaks. Or I will buy the draft detector.
ChrisK, it is not sealed but it's tight and I thought the weight of the motor should be enough.
I have bought 6" pipe (very difficult to find here in Quebec/Canada) to make a chimney.
I will remove the 6 to 5 plywood piece of junk and use 6" all around
 
#14 ·
you may also wish to aim for a more rectangular inlet port, such as the first photo in this thread

http://www.jpthien.com/smf/index.php?topic=563.0

- davezedlee
The person that started this thread has done a LOT of testing with the unit he build and made a few mods that make it better. I suggest that you read through the entire thread and get your ideas. I'm going to rebuild my portable unit and make a fixed station in the corner of my garage/shop. I've created a document for the build (draft 01) mainly using this thread. There are a few other really good posters in the Thien forum. If you go this route I suggest that you subscribe/post in this forum.
 
#15 ·
jgt1942, and bbain32. Good idea, I will try with insence stick to detect leaks. Or I will buy the draft detector.
ChrisK, it is not sealed but it s tight and I thought the weight of the motor should be enough.
I have bought 6" pipe (very difficult to find here in Quebec/Canada) to make a chimney.
I will remove the 6 to 5 plywood piece of junk and use 6" all around

- Johnny Boy
When I built my Thein every joint was sealed. I put Plexiglass for the wall of my unit just because I wanted to see the action. In the grove in the top/bottom of the unit I put caulk in the grove before inserting the Plexiglass. Where the pipe goes up from the Thien into the impeller housing I sealed the pipe with a caulk and the the connection on the impeller housing was also sealed. The intake into the Thein was also seal as well as all the joints around it. The net is that my unit has zero leaks.
 
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