US Patent 10137320 Respirator flow control apparatus and method

A respirator has a shell that defines a breathable air zone for a user wearing the respirator. An air flow control system for the respirator has an air delivery conduit within the shell of the respirator, a valve member moveable relative to the air delivery conduit and within the shell to vary the amount of air flow through the air delivery conduit, and a valve actuator outside of the shell of the respirator. The valve actuator is manipulatable by a user of the respirator while wearing the respirator to control movement of the valve member.