Reverse buckling rupture disk apparatus

An improved reverse buckling rupture disk apparatus comprising:

• a reverse buckling rupture disk including a concave-convex portion connected to an annular flat flange portion by a transition connection;
• at least one support member for supporting said flat flange portion of said rupture disk in a pressure relief area;
• and
• knife means attached to said support member and positioned with respect to the concave-convex portion of said rupture disk whereby upon the reversal thereof, said concave-convex portion is severed by said knife means, said knife means comprising:
• four blade legs positioned at right angles to each other having sharpened cutting edges thereon attached together at the internal ends thereof and attached to said support member at the external ends thereof, each of said blade legs having at least a portion of the cutting edge thereof inclined towards said rupture disk from the internal end to the external end thereof and having a portion of the cutting edge adjacent the transition connection of said rupture disk extending towards the concave-convex portion thereof beyond the plane of the annular flange portion thereof whereby upon reversal of the concave-convex portion of said rupture disk, said concave-convex portion is progressively severed by said cutting edges of said blade legs from points adjacent said transition connection to the center of said concave-convex portion of said rupture disk;
• and
• a spike attached to said knife means at the point where the internal ends of said blade legs are attached together positioned extending towards said rupture disk whereby upon reversal of said concave-convex portion of said rupture disk, said concave-convex portion is punctured by said spike.