Uniformed Services University of the Health Services (USUHS)

This CDC-developed technology relates to improved, full-face flushed-seal personal respirators for lowering costs, improving user mobility, and ensuring occupational health and safety. Currently, the most common type of respirator in use, the negative pressure respirator, seals to a user’s face so that inhaled air is pulled through a purifying filter by inhalation-generated negative pressure; the weakest link in this type of respirator is typically the seal at the face-to-mask interface. When there is face-seal leakage, toxic air will be drawn into the facepiece of the respirator and inhaled by the wearer, though designers and engineers of respirators attempt to minimize this face-seal leakage. Over the last several decades, facepiece design has been optimized by this design approach so that the ambient leakage of half-facepiece respirators and full-facepiece respirators are 10% and 2%, respectively. This technology incorporates an additional element to reduce face-seal leakage and therefore increases user protection. In the respirator described by this technology, a primary sealing element is situated adjacent to the user's breathing space and a secondary sealing element. Exhaled air (i.e., clean air obtained by filter passage) is passed from the breathing space into a flushing channel formed between the primary and secondary seals. If there is leakage in the primary seal, air from this flushing channel leaks into the breathing space rather than toxic, ambient air. Air within the flushing channel will predominately be air that has already passed through the filtering elements. The present invention provides, therefore, an inexpensive respirator which provides significantly more protection than conventional negative-pressure respirators. Further, at present the only alternative respirator types that offer such great levels of user protection are expensive, require heavy batteries and blowers or an airline, and have a limited service life.