US Patent 10335561 Valve

A valve (1, 11, 19) for an inhalation device comprising an interior volume that is delimited at least partially by a valve wall (4, 17, 21), a permanent opening (29) as well as a valve functional area (6), whereby the valve functional area (6) is configured to be at least almost closed below an opening pressure difference and to be open above an opening pressure difference such that above the opening pressure difference, a fluid can flow through the permanent opening (29) into the interior volume and out of the valve functional area (6), the valve comprising an inversion protector that is configured to impede or prevent inversion of the valve wall (4, 17, 21).