Abstract: A bundled tube fuel nozzle is provided. The bundled tube fuel nozzle includes a first end wall, a second end wall, an outer band that extends between the first end wall and the second end wall, and an inner band that extends between the first end wall and the second end wall. The inner band is disposed within the outer band. A bellows wall is disposed between the inner band and the outer band. The bellows wall surrounds the inner band such that a first fuel plenum is defined annularly between the inner band and the bellows wall. The inner band defines a second fuel plenum that is in fluid communication with the first fuel plenum via one or more apertures defined in the inner band. A plurality of tubes extends in an axial direction between the first end wall and the second end wall within the second fuel plenum.

Abstract: This disclosure describes electrical control and power supply systems for powered air-purifying respirators (PAPRs). An exemplary electrical control system for a PAPR may be adapted to control the supply of power between a battery and a blower motor of a filtration unit of the PAPR. The electrical control system may include a plurality of integrated circuits that are capable of meeting minimum operating times while balancing power usage of various “off-the-shelf” components of the filtration unit.