Design questions?

[TallJim27]

I am a newbie to your forum and was all ready to buy a DD but then saw your ideas and am exploring more adaptable solutions. I am going to use a 6.5HP shop vac and a 5 gallon bucket for tools collection and a 20 gal garbage can for my whole house vac separator.
I have been studying your write up and pictures and am wondering a few things.

1. Would it make much difference in the efficiency if the two plates were closer together, i.e. cut down the elbow top and bottom so that the distance between the two plates is nearly equal to the diameter of the elbow inlet hole? I would think that that would allow the chips/dust less room to circulate and be closer to dropping into the can, right?

2. The same with the outlet. Is there a reason to have the length of the tubing (connector) a certain distance inside the lid. I was wondering if it were closer to the bottom plate, would less debris would get into the exhaust (without restricting the flow, of course). I don't know how much "room" is necessary for the cyclone effect but the DD is quite small and works, right?

3. Another idea was to have the exit not straight down but pointed in the opposite direction of the inlet. Would that "kill" the vortex? ...or let less dust exit?

I am sure there has been much experimentation along these lines but I get ideas and have to ask questions. Any input would be appreciated.

[phil (admin)]

I am a newbie to your forum and was all ready to buy a DD but then saw your ideas and am exploring more adaptable solutions. I am going to use a 6.5HP shop vac and a 5 gallon bucket for tools collection and a 20 gal garbage can for my whole house vac separator.
I have been studying your write up and pictures and am wondering a few things.

1. Would it make much difference in the efficiency if the two plates were closer together, i.e. cut down the elbow top and bottom so that the distance between the two plates is nearly equal to the diameter of the elbow inlet hole? I would think that that would allow the chips/dust less room to circulate and be closer to dropping into the can, right?

Yes, and no.  If you get the baffle and lid too close together, with little to no room between the elbow and the baffle, you may find a lot of debris getting stuck there.

2. The same with the outlet. Is there a reason to have the length of the tubing (connector) a certain distance inside the lid. I was wondering if it were closer to the bottom plate, would less debris would get into the exhaust (without restricting the flow, of course). I don't know how much "room" is necessary for the cyclone effect but the DD is quite small and works, right?

Yeah, but this isn't a conventional cyclone, comparisons are difficult.

3. Another idea was to have the exit not straight down but pointed in the opposite direction of the inlet. Would that "kill" the vortex? ...or let less dust exit?

That wouldn't work without also moving the location to off-center.  And it reduced performance on fines.

I am sure there has been much experimentation along these lines but I get ideas and have to ask questions. Any input would be appreciated.

[TallJim27]

Thanks Phil.
I knew these things had probably been tried but didn't want to waste time if they didn't work. The answers seem obvious once you have worked with these things awhile, I guess.

[tvman44]

Is the diameter of the Thien baffle the same as the inside diameter of the can? Or is there some space  between the baffle and the can sides?