Patent ID: 6957653

Claim:
An air purifying respirator of the negative-pressure type comprising: a respirator facepiece adapted for attachment to a user's head to cover at least the mouth and nose of the user, the facepiece being provided with a primary seal that forms a seal with the user's face to achieve a breathing space around the user's mouth and nose separate from the ambient atmosphere outside the breathing space, the facepiece being further provided with a first passageway to permit filtered air to enter the breathing space from the ambient atmosphere when the user inhales; a hood configured to extend over the head and neck of a user providing a secondary seal attached to the respirator facepiece, the secondary seal in use forming a seal with the user's body to achieve a flushing channel separated from the breathing space and bounded by the user's body, the primary seal, the secondary seal and the hood, wherein the hood is comprised of flexible material; a second passageway communicating between the breathing space and the flushing channel to permit air to pass from the breathing space into, and flow through the flushing channel when the user exhales; an outlet passageway in the hood to permit air from the flushing channel to exit from the flushing channel into the ambient atmosphere, whereby any air that leaks through the primary seal into the breathing space is air flowing through the flushing channel; and at least one spacing element within the flushing channel to maintain the flushing channel in an open configuration.