An air trap (110) for a disposable fluid infusion cartridge (100) the air trap (110) comprising upper and lower aspects (501,502) defining a longitudinal axis extending centrally therebetween, an upper fluid input port (503) for receiving the fluid from the heat exchanger (101), a lower fluid output port (505) positioned off-center from the longitudinal axis, an upper air output port (504), and a fluid flow disrupter (601) positioned off-center from the longitudinal axis and proximate the lower fluid output port (505), wherein the fluid input port (503) is positioned off-center for the longitudinal axis of the air-trap (110) to create a vortex within the air-trap (110) pulling air downward toward the fluid output port (505), and further comprising a purging mechanism for purging air from the air trap (110) and preventing air from passing beyond the air trap (110).