Modifying a HF dust collector Question

[Greg Merz]

Guru's
I'm just about to complete the modification of my HF DC. I am creating a stacked DC, 55gal barrel/ inlet ring/ squirl cage with motor/ vented to the outside. Using 5" duct. Inside the inlet ring there is a conic shaped baffle, below that (3-1/4") I installed Phil's baffle. From Phil's baffle to the squirl cage is a total of 8". How far do I need to extend the center pipe?  Does the pipe need to extend below the conic or is it better to keep it above this?

Thanks for the help!

[phil (admin)]

I'd go a little (1-2") below the conic.

Otherwise the conic will shield the outlet from the rotating stream.  So once debris gets above the conic, it would be certain to find the exit tube and then exhaust.

[Greg Merz]

Phil,

Thanks for the reply.

I'm confused, don't you want to shield the outlet from the rotating stream? That way the debri has more time to drop out of the air stream before reaching the exhaust. Or is it that the strength of the rotation is diminished? Also, isn't the conic supposed to keep the debri pointing in the down direction?

[phil (admin)]

You want the outlet tube in the center of the fastest rotation.  That is where the cleanest air will be found.