Compact multi-level inflator

A multi-level inflator for an air bag or other safety restraint device, comprising an elongated pressure vessel having a primary gas generating portion with a first open end and a gas storage portion with a second open end. The primary gas generating portion has a primary initiator and primary gas generating energetics disposed therein, the initiator being mounted on an igniter body secured to and closing the pressure vessel at the first open end thereof. A pressure vessel closure is secured to the second end of the pressure vessel, the closure having an aperture therethrough and a primary rupture disk secured thereto to close the aperture. The gas storage portion has an inert gas therein under a predetermined pressure. A secondary inflator of the all-pyrotechnic type is secured to the pressure vessel and closure at the second end thereof. The secondary inflator comprises a secondary housing having a secondary initiator and secondary gas generating energetics disposed therein. A choke plate having an opening therethrough is positioned between the secondary energetics and the pressure vessel closure. A secondary rupture disk is secured tot he choke plate to close the opening therein.