Abstract: A wearable infusion pump assembly includes a reservoir for receiving an infusible fluid, and an external infusion set configured to deliver the infusible fluid to a user. A fluid delivery system is configured to deliver the infusible fluid from the reservoir to the external infusion set. The fluid delivery system includes a volume sensor assembly, and a pump assembly for extracting a quantity of infusible fluid from the reservoir and providing the quantity of infusible fluid to the volume sensor assembly. The volume sensor assembly is configured to determine the volume of at least a portion of the quantity of fluid. The fluid delivery system further includes at least one optical sensor assembly configured to sense the movement of the pump assembly, a first valve assembly configured to selectively isolate the pump assembly from the reservoir, and a second valve assembly configured to selectively isolate the volume sensor assembly from the external infusion set.

Abstract: In some aspects, methods for providing a uniform shield gas flow for an air-cooled plasma arc torch can include supplying a shield gas to a shield gas flow channel defined by an exterior surface of a nozzle and an interior surface of a shield; flowing the shield gas along the shield gas flow channel; reversing the flow of the shield gas along the shield gas flow channel using a recombination region, the recombination region comprising at least one flow reversing member; and flowing the shield gas from the mixing region to an exit orifice of the shield, thereby producing a substantially uniform shield gas flow at the exit orifice.

Abstract: In some aspects, methods for providing a uniform shield gas flow for an air-cooled plasma arc torch can include supplying a shield gas to a shield gas flow channel defined by an exterior surface of a nozzle and an interior surface of a shield; flowing the shield gas along the shield gas flow channel; reversing the flow of the shield gas along the shield gas flow channel using a recombination region, the recombination region comprising at least one flow reversing member; and flowing the shield gas from the mixing region to an exit orifice of the shield, thereby producing a substantially uniform shield gas flow at the exit orifice.