Servo blower control for powered air purifying respirators

Powered air purifying respirators (PAPRs) are a form of respiratory protection that uses a motor-coupled fan to provide filtered air to a user through a positive pressure mask. Three types of PAPR devices have been developed of which breath-responsive PAPRs are the most recent. The benefits of breath-responsive PAPRs have been identified and regulatory performance requirements have been put in place for these devices, however, no devices have been certified by any regulatory agencies. This study proposes a novel conceptual design for a breath-responsive PAPR and describes a dynamic simulation of the characteristics of this new PAPR compared to a constant flow design as exercised by a simulated breathing cycle. Additionally, this study describes a prototype of the breath-responsive concept with experimental evaluation of the prototype against regulatory requirements and conceptual design targets.