Thanks for posting that.
I have one that is like a square column in my shop with 8 outlets that goes from floor to ceiling It has an6" duct straight out the top and 2 6" di, inlets and six 4" outlets around it.
The only thing I question about this one is the the inlets are 90deg. to the vertical airflow. When this happens it cuts down on the airflow drastically.
I made my inlets at 45 deg.to the vertcal to help maintain as much air flow as possible.
the one shown might act as a cyclone and the heavier chips might want to settle out and fall to the bottom of the box, just a guess on my part.
In any event airflow turning on a 90 deg. will be greatly reduced.
Herb