Ventilation check valve v2

This is a vertical-only air duct valve designed to: Prevent backflow of air, Remain closed when idle, and Open only when a fan or extractor is actively running. The blades include compartments where you can insert fishing sinker balls to adjust the closing force. This allows fine-tuning so that your specific extractor can open the valve under normal operating pressure while ensuring it stays sealed otherwise. Additional features: The valve can be manually locked in the closed position by rotating the central shaft 90°. It can also be kept open using small tabs that hang from the blades. Vertical installation is required for correct operation. For different duct diameters, please edit the parameters in the raw design file instead of scaling, to avoid issues with fit or mechanics. Assembly guidance is included in the .3mf file, which contains all the parts properly positioned and oriented for reference. ⚠️ Some parts require a 0.2 mm nozzle for optimal detail and function. ✅ A simplified