Poppet valve with a frangible sealing disc for a pressure vessel

A valve assembly for a pressure vessel, comprising:

• a valve housing operatively associated with an outlet of the pressure vessel;
• a frangible disc sealing the outlet of the pressure vessel;
• a poppet valve mounted for movement within the valve housing between a first position supporting the frangible disc within the outlet of the pressure vessel and a second position spaced apart from the frangible disc to permit the frangible disc to burst under pressure and permit the egress of pressurized material from the pressure vessel through the outlet, wherein the poppet valve includes a cylindrical head portion and an elongated valve stem depending from the head portion and defining a longitudinal axis;
• a locking mechanism for releasably securing the poppet valve in the first position, wherein the locking mechanism includes a valve stem extension having an annular retention slot formed in an outer periphery thereof, wherein the locking mechanism further includes a collet associated with the valve housing and surrounding the valve stem extension, the collet including a radially inwardly projecting retainer ring adapted and configured to releasably engage the annular retention slot in the valve stem extension;
• an actuation mechanism for releasing the locking mechanism, to allow the poppet valve to move from the first position to the second position under pressure from the pressure vessel;
• and
• a lock ring operatively associated with the actuation mechanism through a plunger, the lock ring including an upstanding annular wall for maintaining the retainer ring of the collet in the retention slot of the valve stem extension when the poppet valve is in the first position, wherein the collet includes a plurality of circumferentially spaced apart deflectable locking fingers each including a portion of the annular retainer ring, and wherein the deflectable locking fingers each include a radially outwardly projecting rib positioned to bear against the annular wall of the lock ring when the poppet valve is in the first position.