Internal Thein baffle or Top Hat Separator?

[AldoS]

 Hello all,

I was reviewing this blog and I was wondering if any of you could give me your personal opinion on whether I should go the route of an internal Thein baffle or put the extra effort in to build a Thein top hat separator.

I have a small personal woodworking shop, and space is a premium.  I have an old 2Hp import dust collector that I just purchased an new canister for.  Ideally I would prefer to use the internal baffle to minimize the overall size of the system.  I can live with having to deal with the hassles of dealing with the DC chip bag and dealing with the chips flowing through the impeller.  What I am concerned about is the efficiency of the internal baffle as compared to the top hat separator.  I read that the internal baffle would be more efficient than the top hat separator because of the static pressure drop associated with the additional separator canister.  Which in your opinion is the more efficient system, and why?  Which in your opinion would be best in terms of minimizing debris deposit in the canister and why (is there a noticeable difference)?  Can you recommend a good set of plans or other setup information for the internal baffle?  Again, from your personal experience which of the two would you go with in a small shop.

Thank you in advance for any help.  I am new to dust collection and could use all the help I can get.

[BernardNaish]

Hi and welcome. I think you would be best advised to build a separator just like retired2's build. This reduces the space you would need as it gets rid of your cart and integrates your DC into the Thien TH. It is possibly easier to make than putting a baffle into your DC. It works very well as shown in his unique data. The most important point of collecting before the DC is that it greatly reduces the dust getting to your filter. It must also be a bonus to get rid of the extreme hassle of changing the plastic bag on a DC.

His build is here:

http://www.jpthien.com/smf/index.php?topic=563.msg3024#msg3024

Good luck with your build and I hope you can tell us how well it works and join in with this great forum.

[BernardNaish]

Oh! I forgot to say if you build retired2's top hat use polycarbonate sheet as it is tough and much more flexible than acrylic. Acrylic often cracks when bent or otherwise stressed.

[AldoS]

Thank you.

Can you tell me what the purpose of the bell mouth is? 
Does any one have any idea of the efficiency loss of a top hat design versus an internal baffle?  Also, are there any numbers on how much cleaner the canister filter will be with a top hat separator versus the internal baffle (i.e., are we talking about a relatively minor improvement)/

Cheers
Aldo

[BernardNaish]

Hi Aldo, There is no comparative data. retired2's build gives details of bellmouth oulet pipes and flow straighteners both of which probably give improvements in separation. The straighteners are the more important. I know it is a long thread but you just need to read it through possibly twice. You will spend a day being fascinated.  Good wood shaping. Bernard

[phil (admin)]

The losses from a baffle INSIDE the DC's ring are substantially lower than those of a top-hat separator.  Fine Woodworking's test indicated they saw little initial loss from adding the baffle to a Jet dust collector.

It is probably substantially easier to add a baffle to your existing DC ring than building a top-hat, as well.

The only advantage to the top hat really is that it prevents larger chunks of wood or screws or whatever from hitting your blower wheel.  But the blower wheels inside single stage DC's are designed with this possibility in mind.

[galerdude]

The losses from a baffle INSIDE the DC's ring are substantially lower than those of a top-hat separator.  Fine Woodworking's test indicated they saw little initial loss from adding the baffle to a Jet dust collector.

It is probably substantially easier to add a baffle to your existing DC ring than building a top-hat, as well.

The only advantage to the top hat really is that it prevents larger chunks of wood or screws or whatever from hitting your blower wheel.  But the blower wheels inside single stage DC's are designed with this possibility in mind.

Was totally unaware of this. Awesome info!
Thanks for posting this!!!

[AldoS]

Thank you Phil.

Any idea on whether the canister will be "substantially" or "marginally" cleaner with the Top Hat version over the Internal Baffle (i.e., for comparable periods of use)?  The answer to this question will likely dictate which way I go.

Kindest regards
Aldo

[BernardNaish]

Hi Aldo, I am sorry that it looks like I gave you some unhelpfull information. B

[AldoS]

Not at all!

I may very well go the separator route if I can determine that it will give me a longer canister life. 

Thanks again
Aldo

[BernardNaish]

You could of course put a Thien baffle in the DC with, say, a half inch wide slot. This would take out fine dust. AND a top hat before the fan with say a 1 1/2" wide slot to take out the coarse stuff with the decided advantage that the bin is easy to empty. Phils says it is easier to put a baffle in the DC so not too much more work. I would think that this is probably a good way to keep the filter can as dust free as is possible. Perhaps others can comment? I am certainly going to have a look at my DC tomorrow to see if I can fit a baffle in it to back up my pre-fan Thien. I emptied my bin today and it took 2 minutes.

[phil (admin)]

You could of course put a Thien baffle in the DC with, say, a half inch wide slot. This would take out fine dust. AND a top hat before the fan with say a 1 1/2" wide slot to take out the coarse stuff with the decided advantage that the bin is easy to empty. Phils says it is easier to put a baffle in the DC so not too much more work. I would think that this is probably a good way to keep the filter can as dust free as is possible. Perhaps others can comment? I am certainly going to have a look at my DC tomorrow to see if I can fit a baffle in it to back up my pre-fan Thien. I emptied my bin today and it took 2 minutes.

I think you nailed it here.

I'd put a baffle in the DC ring.  Later on, if he wants something easier to empty than the bottom bag, he can build a top-hat to go in front of the jointer and planer.

[AldoS]

Thanks Phil, Bernard

That approach will likely work since my planar and jointer stations are not fixed and need to be moved into place for use.  A small (storable) separator may help with large chip removal in this case and reduce DC chip bag exchanges.

Phil,  do you have a link to the Fine Woodworking article?  I don't think I have seen that one.

Kindest regards
Aldo

[phil (admin)]

Unfortunately I do not have a link to the FWW article.  I imagine one has to join the FWW site and access it via the archive.

[ninja]

my father's work shop is small as yours, I made DC for him. here is  my built http://www.jpthien.com/smf/index.php?topic=1106.0 if you need, I can send you more pictures and CAD diagram , because I used laster cut