Patent attributes
Exhalation and inhalation valves that are sized and adapted to fit on a mask body of a personal respiratory protection device. The exhalation and inhalation valves comprise a valve seat that has a seal surface and an orifice through which an exhale flow stream may pass to leave the interior gas space. A flexible flap is mounted to the valve seat such that the flap makes contact with the seal surface when the valve is in its closed position and such that the flap can flex away from the seal surface during an exhalation to allow exhaled air to pass through the orifice to ultimately enter an exterior gas space. The flexible flap has at least first and second juxtaposed layers where at least one of the layers is stiffer or has a different elastic modulus than the other layer. These valves provide extraordinarily lower pressure drop in use, and they operate more efficiently and require less actuation power to operate. The end user therefore derives greater comfort when wearing a respiratory mask that uses the inventive valve.
