Inlet Elbow Orientation Question

[bill70j]

Thanks to Phil for this innovative, most useful device, and to the contributors to this Board, the ideas of whom I have liberally stolen.

Anyway, I am in the midst of designing a mobile base for my HF/Thien Separator and have a question about orienting the elbow that the dust hose attaches to, which is coupled to inlet elbow feeding the separator.  I am using 4" ABS SD pipe.  Should the dust hose elbow be coplaner with the separator inlet elbow, or rotated 90 or 270 deg on the axis - or does it matter?

Thanks for any advice!

[bill70j]

Well, I think I answered my own question - sort of.  I tested the system both ways - with the elbow aligned in the same plane with the separator inlet as shown in the image below - and with it rotated 90 deg.  I loaded my bench planer with sacrificial knives and planed several pieces of MDF under controlled conditions.  In both cases virtually all the dust ended up in the separator, with very little ending up in the poly bag.  So I ended up building the system as shown in the images, figuring that one fewer change in flow direction would mean that much less friction loss.

My completed system is shown below.  Thanks to skillington and Robert Wong, whose design concepts I merely copied.  And of course to Phil.