So, to collectively brainstorm here - how would you go about making a DIY PVC version of this? I know PVC pipe - I assume for an 8" ducting I would need 10" or so PVC piping or 12" and taper it down to 8"?
If you look at the active air versions - they have a different design - like a hollow inside.
Tree Beard - could you refill those active air ones like you can with the regular ones?
How to Refill the Activated Carbon in a Duct Carbon Filter - YouTube
I have refilled a vivosun 6" filter. It is a colossal pain in the ass. It's also messy. That said, it is and has been working as good or better than the original for a couple months now. But filling a straight pvc pipe, would be so much easier. The vivosun has a fabric (think, pantyhose) that contains all the charcoal and most of the dust inside the mesh parts of the filter. That opening is only like an I ch wide all the way around so it's really tough to fill it without making a mess, keeping the liner in place, and doing all that while keeping the inner mesh centered so the end caps will go back on correctly.
My thoughts on the inline pvc filter would be to get the diameter you need, get some couplers with a metal mesh or screen for the ends, get some sort of fine mesh bag that's as big or bigger than the pvc, put the bag in the pipe like a trash bag in a can, fill it up, tap or vibrate it to get it to settle, put caps on and voila!!
Edited to add: you could use a bung on the side like they do for filling and glue both end on or I would probably just glue one end on and press the other end on. I think this would work with the mesh bag method much better than trying to pour the charcoal into a bag through a much smaller opening. Of course, if you could get or make end caps with the fine mesh incorporated into them, you wouldn't need a bag on the inside.
