Patent ID: 7296568

Claim:
A respirator comprising a facepiece defining an interior chamber for filtered air and including at least one inhalation opening for passage of filtered air from the atmosphere to the interior chamber; at least one exhalation opening for passage of air from the interior chamber to the atmosphere; and a filtration canister removably mounted to the facepiece and in fluid communication with the at least one inhalation opening for passage of purified atmospheric air to the facepiece interior chamber; a self-sealing valve mounted in the at least one inhalation opening and adapted to seal the at least one inhalation opening to prevent inhalation of air therethrough when the filtration canister is removed from the facepiece and to open the at least one inhalation opening to permit inhalation of air therethrough when the filter canister is mounted to the facepiece; and a speech transmitter and exhalation valve module mounted in the at least one exhalation opening and adapted to seal the at least one exhalation opening to prevent inhalation of air therethrough and to open the at least one exhalation opening to permit exhalation of air therethrough, the speech transmitter and exhalation valve module comprising: a module body having an inner face, an outer face and an outer wall; a airflow cavity defined by an inner side wall of the module body and extending between openings in the inner and outer faces of the module for fluidly connecting the inner face and the outer face; an airflow guide positioned within the airflow cavity; and an outlet valve, mounted to the module body and in the airflow cavity, and adapted to close and fluidly seal the airflow cavity during inhalation and to open during exhalation, characterized in that: the inner side wall of the module forms with the airflow guide and the outlet valve an airflow channel in the form of a horn expansion contour during exhalation when the outlet valve is in an open position.