POWERED AIR PURIFYING RESPIRATOR WITH NOISE REDUCING PLENUM

摘要

The present description provides a respiratory protection device including a shell defining an interior zone around at least a portion of a head of a user and a curved air delivery plenum within the shell. The air delivery plenum includes a plenum inlet, a plenum outlet, and first and second plenum subsections positioned between the plenum inlet and outlet, the second plenum subsection having a maximum cross-sectional area (Amax2) and including a second plenum inlet having a cross-sectional area (Ai2). The air delivery plenum is curved along a longitudinal axis extending along the air delivery plenum in a direction of airflow, and (Amax2) > 1.5 (Ai2).