Furnace Vent Cap

UPDATE: I added a new v7 version. I've tweaked the internal structure for easier printing (no need for supports) and also filleted the interior and exterior edges, to promote smoother airflow on the inside and a smoother surface on the outside. Haven't printed this version, so any feedback is appreciated.

I designed this cap for my furnace vent, as I was getting back draft issues that were triggering my pressure switches during high wind events (my vents face in to the wind).

Haven't tried printing without supports, I recommend orienting so that the opening is facing up. I've uploaded the cura file that should contain my cylinder support, which can be pushed out and then trimmed to remove.

This fits over an elbow joint that fits a 40mm PVC pipe - the fitted diameter is 70mm. You may need to resize for your use case.