The simplest valve for exhalation (air exhaust)

thingiverse

Here's a simple exhaust valve that works great right out of the box. It's very easy to use and gets the job done efficiently. This valve is quick to print, taking just 13 minutes to complete. Plus, it's universal, fitting snugly into any hole with a diameter of 19mm after a quick glue application. You can easily add this valve - or even a pair of them - to almost any mask you've already made. Simply cut off the excess length of the connecting tube once the glue has dried. To assemble, all you need is a tightening screw with a diameter between 1.6 and 3 mm (2mm being ideal). For the rubber diaphragm, you can use a piece cut from household gloves or any other thin rubber band. When assembling the valve and cover, make sure to align the wide plates and clamp a rubber diaphragm in between them. This design is optimized for printing with a 0.4 nozzle at a flow rate of 0.48, making it easy to produce with minimal hassle. I've included the original project file in SOLIDWORKS, complete with main dimensions listed in the "Equations" section.