Automatic air vent - table tennis ball based

I needed an air eliminator for my low-pressure water system, so I designed one using a ping pong ball as the float. When the water reaches full level, the ball presses against a rubber gasket (12/24x2 mm) to seal the chamber, and it opens when sufficient air accumulates. The unit connects to the system via a heat-inserted 1/2" BSPP nipple. The lid is held by M3 screws (heat-inserted threaded inserts) and it sits on a 45/49 rubber o-ring. 

Tested up to 2 bars.