Rupture disc with selectively positioned initial buckling

A rupture disc assembly comprising:

• (a) a reverse buckling rupture disc having a prebulged dome with a radially outward periphery and a crown at an apex of said dome, a flange connected to the periphery of said dome and extending radially outwardly therefrom, and a transition region between said dome and said flange;
• said dome having a concave side and a convex side;
• (b) mounting means for securing said disc in a vent such that the disc prevents passage of fluid through the vent until rupture of the disc;
• (c) said mounting means including a support ring positioned on a side of said disc associated with said dome concave side;
• said support ring generally supporting said flange and being substantially open opposite said dome such that on reversal of said dome said dome passes through said support ring;
• and said support ring supporting a substantially continuous first portion of said transition region when pressure is applied to the convex side of said dome;
• said support ring having upper and lower substantially parallel and planar surfaces;
• (d) said disc including a tab area defined thereon in a second portion of said transition region and a tear area located in a remainder of said transition region;
• said disc tearing in said tear area upon rupture of the disc and said tab area remaining untorn upon rupture of the disc so as to maintain said dome connected to said flange after rupture of said disc;
• and
• (e) said support ring including buckling initiating means comprising a discontinuity therein on the planar surface generally immediately adjacent to said second portion of the transition region located in the tab area such that said discontinuity is operably positioned immediately downstream of said second portion of said transition region located in said tab area, so as to initiate original buckling of said dome between said tab area and said crown;
• said discontinuity being located within the planes of said substantially parallel and planar surfaces;
• (f) whereby when sufficient differential pressure is applied to said dome convex side to buckle said dome, said dome first buckles between said crown and said tab region, subsequently said dome reverses and passes through said support ring and thereafter tears from said flange along said tear area.

In a reverse buckling rupture disc assembly including a disc having a centrally located pre-bulged dome with a concave side, a convex side and a crown, a flange extending radially outward from said dome and a transition region between said dome and said flange and further including a downstream support ring for supporting said disc on the concave side thereof and having a substantial opening therethrough opposite said dome;

• said support ring having upper and lower substantially parallel and planar surfaces;
• the improvement wherein:
• (a) said support ring includes a failure initiating discontinuity therein on the planar surface operably positioned immediately beneath and directly adjacent a first portion of said transition area which is generally closest to a location on the dome whereat initial buckling is desired;
• said discontinuity being located within the planes of said substantially parallel and planar surfaces;
• and
• (b) said support ring supports substantially all of the transition area outside said transition area first portion;
• (c) whereby when said disc has sufficient differential pressure applied to said convex side to cause buckling of said dome, said dome first buckles between said dome crown and said failure initiating depression.