Spool Louver (WIP)

thingiverse

I've got a grow tent sitting around. I picked it up as an enclosure for my HE3D K280, a massive printer that's more beast than machine. When COVID hit, I decided to turn the tent into a sanitizer for large items, groceries, Amazon boxes, clothing, and anything else that needed some disinfecting. I added a room ozone generator, a UVC lamp, and built a purge unit out of an old ventilator fan from an ancient piece of equipment (steel frame? Check! High CFM? Check! Loud as hell? Double check!). I automated it with smart plugs and an Alexa routine so I can toss everything in, seal it up, walk away, and let the robot handle it. The problem is that purging creates a vacuum inside the tent. All the flaps and ventholes are sealed to keep ozone in and oxygen out. So I needed a self-actuating vent cover that wouldn't take forever to print. I realized that discarded spools (why do I have so many?) fit the holes perfectly, requiring only a 70-something mm hole. That's what this is: a self-actuating intake louver that fits inside a 72.5mm spool hole. Gravity should close it, and sufficient airflow should open it.